Audi compressor won’t engage? (Solution)

  • Using a fused 12-volt jumper, apply power to pin T14/10 (green/black). The compressor clutch should engage. If the compressor does not engage, check for a wiring harness open circuit or loss of ground at the compressor.

What causes a compressor to not engage?

One of the reasons why compressors do not engage is because of a low pressure lockout, a poor ground, a bad clutch coil, an opening in the wire to the clutch coil, or simply a blown fuse. There are several ways A/C compressor clutches receive power. With engine running, you will want to set the A/C to MAX.

Why is my car AC compressor clutch not engaging?

Why AC clutch won’t engage If the clutch doesn’t engage, the problem could be a blown fuse, an open in the wire to the clutch coil, a bad clutch coil, a poor ground, a low pressure switch lockout, or even a bad engine coolant temperature switch.

How do I manually engage my AC compressor?

Take the fused jumper wire and connect its one end to that side of the wire connector that was connected to the compressor. Attach the other end of the jumper wire to the positive terminal of the battery. It will supply the battery voltage to the compressor clutch, allowing it to engage manually.

How do I know if my compressor clutch is bad?

Bad AC Compressor Clutch Symptoms

  1. Higher Cabin Temperatures. The most common sign of all bad ac compressor clutch symptoms is a higher cabin temperature than usually during hot days when you need the A/C.
  2. Loud Noises.
  3. Clutch Stopped Moving.
  4. Inability to Turn Air On or Off.
  5. Leaking Refrigerant.

What causes low pressure lockout?

When a unit cycles or locks out on the low pressure switch, what should you look for? the most common cause is low air flowacross the evaporator. look for dirty filters, dirty evaporator coil, dirty blower wheel.

What causes AC compressor to lock up?

Some of the causes for car air conditioning compressor locking up include incorrect or low quality refrigerant being used, low coolant levels, and improper lubrication. You need to get your car checked out before any issue worsens.

How do I know if my AC clutch relay is bad?

One of the most obvious signs that the AC relay may have a problem is that the compressor is not coming on at all. In most cases, when the AC is turned on you will be able to hear the compressor switch on. It will usually produce a familiar clicking noise from the clutch being activated.

What module turns the compressor clutch on?

An AC clutch cycling switch is used to determine low side A/C pressure (which is directly proportional to temperature). This information is then used by the electronic control module (ECM) to control the compressor clutch.

How do I reset my AC compressor?

How to Reset an Air Conditioner

  1. Power down your AC. Start at your circuit breaker panel and flip the breaker that powers your AC.
  2. Find the button. Most air conditioning units are equipped with a reset button.
  3. Hold down the reset button for 3 to 5 seconds and then release.
  4. Restore power to your AC.

Can you replace AC clutch without removing compressor?

Yes you can just replace the clutch pulley on the a/c compressor. The issue that you may have is the pulley bearing seized up and may have spun on the front of the compressor nose cone and will damage it. You may need to replace compressor.

Audi compressor won’t engage

On the cars mentioned below, Audi has issued a service bulletin15-69 (2020124/13) to remedy an Audi air conditioning compressor that would not activate. In addition to the fact that an Audi compressor would not engage, you may also encounter the following error messages: DTC 00457 – Vehicle Electrical System Control Module – J519 is a diagnostic trouble code. Temperature and pressure sensors for the air conditioning system DTC 00256: G395: Incorrect signal No signal or transmission is received by the A/C pressure/temperature sensor (DTC 00256).

DT The code CDTC 00256 identifies an incorrect signal from an A/C pressure/temperature sensor (G395).

Read further

Audi compressor won’t engage affected by service bulletin15-69 (2020124/13)

A4 The VIN range for 2009-2012 vehicles is 000001 – 999999A4. N000001 – N045670A4 are the VIN numbers for 2013. VIN range A000001 – A231729A5 for 2013 vehicles The VIN range for 2008-2012 vehicles is 000001 – 999999A5. VIN range: 000001 – 071355S5 / RS 5 for the 2013 model year VIN range 900000 – 902787A5 for 2013 vehicles Cabriolet The VIN range for 2010-2012 vehicles is 000001 – 999999A5. Cabriolet VIN range 000001 – 015616S5 for 2013 vehicles RS5 Cabriolet / Cabriolet / RS5 Cabriolet VIN range 900000 – 900501A6 for 2013 vehicles The VIN range for 2005-2012 vehicles is 000001 – 999999A6.

VIN range 000001 – 029602Q5 for 2013 vehicles From 2009 to 2012, the numbers 000001 through 999999Q5 were used.

Audi AC compressor won’t engage symptoms

A4 000001 – 999999A4 are the VIN numbers for vehicles manufactured between 2009 and 2012. N000001 – N045670A4 is the VIN range for 2013. A000001 – A231729A5 are the VINs for the 2013 model year. Vehicle identification number (VIN) range 000001-999999A5 for 2008-2012 models. Vehicle identification number (VIN) range 000001 – 071355S5 / RS 5 2013 VIN range 900000 – 902787A5 for the 2013 model year Cabriolet VIN range: 000001 – 999999A5 for 2010-2012 vehicles. Cabriolet VIN range: 000001 – 015616S5 for the 2013 model year The Cabriolet (RS5 Cabriolet) is a convertible sports car.

VIN range: 000001 – 134357A7 for the 2013 model year.

VIN range: 000001 – 134357A8 for the 2013 model year 0000001 to 999999A8 are the VIN numbers for vehicles manufactured between 2004 and 2012. VIN range: 000001 – 029602Q5 for 2013 vehicles. 000001 – 999999Q5 (2009 – 2012) VIN range: 000001 – 083307 for the 2013 model year

Fix for Audi compressor won’t engage

An upgraded pressure sensor has been made available by Audi, which has resolved the issue. Starting with the G395 pressure sensor, look for signs of a refrigerant leak to narrow down your diagnosis. If you discover a leak, replace the sensor with the most recent version. If the refrigerant pressures are good and there is no evidence of a leak, proceed with the regular tests. 4H0959126A Pressure sensor 4H0959126A 4H0959126A O-ring with the part number 17H0820896 Next, look for cuts or chaffing in the LIN cable that connects the vehicle electrical system control module to the sensor.

The year is 2019.

Rick Muscoplat posted a blog entry on

What Should I Do If AC Compressor Clutch Is Not Engaging?

So, what should I do if the AC compressor clutch is not working properly? Consider the following scenario: you have an automobile, and everything works well. When you switch on the air conditioner, on the other hand, only warm air is blown. What may be the source of the problem? If your air conditioner’s compressor clutch suddenly stops operating and does not engage, this might be the cause of your air conditioner’s failure to perform correctly. It is possible that the compressor is experiencing a significant problem or a minor one.

  • You may want to perform a visual check of the AC compressor clutch to see if you can identify what is causing the clutch to fail to engage.
  • Even if you have recently refilled your air conditioning system with refrigerant, if the AC compressor is unable to function properly, you may experience warm air.
  • We’ll go through some of the probable issues and remedies for a compressor clutch that isn’t working properly.
  • Let’s make sure your air conditioner is in good operating order before we get started.

Do a Visual Inspection

If the AC compressor clutch does not engage, what should I do? If you have an automobile, everything should be running well. It blasts heated air only when the air conditioner is turned on, though. Can you tell me what could be the issue? This might be the reason why your air conditioner isn’t working correctly if the AC compressor clutch suddenly stops working and doesn’t engage. Either a big or a little problem with the compressor might exist. The absence of engagement of the compressor clutch indicates that there is an electrical or mechanical problem with the compressor.

If the AC is not delivering cool air into the vehicle, you may want to replace the compressor clutch.

To rule out other potential problems, you may want to check the enginecoolant and engine oil, but the clutch is the component that must be operational in order for the AC to function properly.

If your compressor clutch is not engaging, we’ll go over some of the probable causes and remedies. It might be caused by anything from a blockage in the refrigerant circuit to a faulty electrical connection. First, let’s check to see if your air conditioner is functioning properly.

  1. In order to test the clutch, you may either acquire a power probe or try to make do with a wire, as seen in the video above. In order to avoid purchasing anything, test the air conditioner with the engine running, as stated later. Also check to verify if the AC clutch engages when power is applied. Warning: If you are confused about which circuits to test, get assistance or try a different way to avoid causing more issues. Examine the compressor and make certain that the belt that passes across the pulley is in excellent working order – if the belt is slipping or has become worn, it will need to be tightened or replaced. Keep an eye out for corrosion around the clutch plate. When rust appears on the compressor, it might be an indication that it is old and may just need to be replaced since it has worn down and become damaged. Check the wiring to the clutch – if the wires are not correctly connected, it might have an influence on how well the compressor operates. In order to produce enough electricity, the wires must be properly connected and in excellent shape. Additionally, the high pressure switch and evaporator temperature sensor may be broken or have loose wires
  2. Therefore, It is critical for you to understand the fundamentals of a few components before proceeding to the next phase. Because of the low-pressure switch, the compressor clutch relay is turned on and off in some of the vehicles. In a controlled system, the relay, on the other hand, is grounded by a computer. In order to diagnose the problem more quickly, thoroughly check all of the system’s components. You might get a digital multimeter and use it to verify the voltage and ground at the relocated connection. If you are unable to obtain a voltage measurement, the fuse should be checked. It is possible that the automobile will need to be started even if the engine is not running. If everything is in working order with the fuse, you should check the clutch relay. Removing it allows you to examine the relay for power and ground by pulling it out of the socket and checking its terminals. Make a visual inspection of your air conditioning system for leaks – check for leaks coming from the condenser, receiver, or any other spots where metal pipe connections are formed.

What to look for during your visual inspection

Take a look at these illustrations for more information on how your air conditioning compressor operates and what to check for. Whenever possible, allow the engine to cool completely before working on or inspecting the engine. When physically checking parts, wearing gloves will be quite beneficial. This image is from of

Turn On the Engine Inspection

After you have completed your visual check, start the engine by pressing the following button: 1. With the engine running, set the air conditioning up to maximum – you’ll be checking for any problems with the serpentine belt. After that, have a check at the compressor clutch. Following that, you’ll need to wait for a few minutes for the compressor clutch to engage and begin spinning as well, which may take up to a minute. 2. If you’ve waited many minutes while the engine is running and the air conditioning is set to the highest setting and the clutch is still not engaging, there’s something wrong with the vehicle.

  1. 3.
  2. Here’s a video that demonstrates how to locate an air conditioning leak using a fluorescent dye: How to Find an AC Leak.
  3. Image courtesy of: You may also experiment with a refrigerant leak detector before purchasing a can of halt leak.
  4. This is an example of a refrigerant leak detector.

Being Low on Refrigerant

Another possible explanation for the AC compressor clutch not engaging is a low level of coolant in the system. The sensors in your air conditioner will determine whether or not the pressure is correct. If something is turned off, the air conditioning compressor may not turn on. Low coolant content or pressure can be hazardous to the operation of your vehicle’s cooling system. In order to cool down components and lubricate mechanical parts, the compressor relies on the oils contained inside the refrigerant.

An overcharged air conditioning system will not have the proper pressures, resulting in the clutch failing to engage and the pressure wearing out parts more quickly.

This is a common practice.

Actually, at this point, it’s possible that you’ve done some major damage to your compressor.

Tip on Adding Refrigerant

Use refrigerant only if you have done your research and are confident in your comprehension of how much pressure your vehicle’s air conditioning system demands. Consider reading this article on AC system oil if you feel that a significant amount of AC refrigerant has been leaking from your unit. It is possible that seeing a professional to evacuate your air conditioning system (as this is the only legal technique to remove refrigerant) before adding refrigerant is the best answer. You can be confident that you are adding the right amount of refrigerant to your system this way.

  1. A diagnostic gauge for the air conditioning system will provide you with a clear idea of what the high and low pressures are.
  2. When there is a leak, moisture and air are allowed to enter the system.
  3. This has the potential to destabilize the system.
  4. Follow the instructions on the diagnostic tool carefully when attaching it to your air conditioning system.

Then you may switch on the air conditioning system and set the temperature to high. As the clutch engages, the air conditioner should cycle the refrigerant, causing the pressure measurement to vary somewhat.

Is My Compressor broken?

Image courtesy of: Several factors can contribute to the inability of your compressor to function properly. If you’ve checked the electrical system and the clutch and found nothing amiss, it’s possible that your compressor has an internal mechanical or electrical fault that has to be addressed. If the compressor is faulty, I would propose that you replace the complete unit with another one. The reason for this is because by replacing the old one with a new one, you will most likely save both time and money.

  1. When removing one and replacing it with a new one, the work is time-consuming.
  2. Furthermore, purchasing a new compressor is not significantly more expensive than having an old one fixed.
  3. If you’re interested in installing your own compressor, you should watch this video (How to Replace an AC Compressor in Your Car) first.
  4. (How to Unlock an AC Compressor That Has Glocked Up)

Other Parts to Check

It is also necessary to inspect the condenser surrounding the connection where the compressor’s output line is connected tothe condenser if your compressor has become unresponsive. It is likely that you may uncover a little piece of metal that can block your condenser. Therefore, you may need to replace it if you are unable to remove the metal fragments from it. It is possible to examine thedrier / receiver, which helps filter and store the liquid refrigerant as it begins to convert back into a gas, for sounds or foul odors coming from the air conditioning system inside the car.

  • Typically, the evaporator coil is situated within the automobile cabin, and air is forced over it to cool the air down.
  • It may be prohibitively expensive to replace, but if it is leaking or damaged, it should be repaired or replaced.
  • If it is not operating correctly, you may notice that the AC compressor does not shut off and that frost has accumulated around the AC vents.
  • It is possible that replacing this valve will not be prohibitively expensive, and it will certainly be a less difficult process than replacing an air conditioning compressor.
  • If a fuse blows, it is a simple matter to replace it.
See also:  Chrysler Change Oil Reset Procedures? (Best solution)

Using a Mechanic

When you’ve thoroughly studied the problem and conducted your study and have decided that you do not want to perform the repair work yourself, you may feel more confidence when contracting the service to a technician. Because you are more knowledgeable about what is wrong with your vehicle and what to expect when repairs are made, you can communicate with the technician in a way that demonstrates that you are expecting a quality service for the price you are paying. Asking them to repair an air conditioner compressor will cost a little money, but it will hurt less for certain people who are familiar with the process of repair.

Because this sort of profession has a significant learning curve, extreme caution should be exercised. If you still want to do it yourself, make sure you complete all of your homework beforehand and enlist the assistance of a buddy.

Our Advice

Start with the most basic methods of checking the AC compressor to see if they will aid you in determining what is wrong with it. Then you can go on to do other inspections until you no longer feel interested or competent to do so any more. You want to be able to finish a work that you start so that you aren’t irritated and don’t have to spend time addressing difficulties that you made by mistake. Starting small might assist you in determining what you are capable of and willing to undertake.

The best option in most cases is to call on the help of a buddy who has previous expertise starting and engaging the compressor’s clutch on their own.

8 Reasons an A/C Compressor Clutch Won’t Engage (and How to Jump It)

The most recent update was made on June 28, 2021. Few car amenities are as well-liked by the ordinary motorist as air conditioning, especially during the sweltering summer months. The air conditioning system in a car effectively stops the summer heat in its tracks, replacing it with a soothing coolness. Are you looking for a reliable online repair manual? The top five choices may be found by clicking here. Nowadays, sophisticated A/C systems are also equipped with dual-climate control, which allows each individual passenger in a car to individually regulate the temperature in the cabin.

  1. Unfortunately, air conditioning-related problems of varied severity can and do arise from time to time.
  2. One of the most prevalent types of A/C system-related defects is that of an inoperable A/C compressor clutch, which is one of the most common symptoms.
  3. Find out more about the reasons of an inoperable A/C compressor clutch and how to resolve the problem if it occurs again in the future by continuing reading this article.
  4. Also see: 8 Reasons Why Your Air Conditioner Isn’t Blowing Cold Air

What is an A/C Compressor Clutch?

It is the air conditioner compressor clutch in a vehicle that is responsible for distributing power to the internal drive components of an A/C compressor’s internal drive system. An air conditioning compressor pulley free spools when the air conditioner is switched off in a car. As a result, no rotational force is delivered to the driveshaft of the air conditioning compressor. This reduces the amount of additional stress exerted on a vehicle’s engine and reduces the amount of internal compressor wear experienced.

This energization of the clutch coil generates a magnetic field, which aids in clutch engagement by drawing the clutch’s drive plate inward, where it meshes with the clutch body/compressor pulley, therefore increasing clutch engagement.

When the air conditioning system in a car is switched off, the clutch coil that is associated with it is de-energized. As a result, the clutch on the A/C system is disengaged. Car A/C Condenser Symptoms: What You Should Look For

Causes of an A/C Compressor Clutch That Won’t Engage

For a variety of reasons, including electrical issues, an air conditioning compressor clutch may fail to engage when it should. The actual reason of such problems varies from one car type to the next, as well as from one year to the next. The following are some of the most prevalent reasons of an inoperable fan A/C compressor clutch, as identified by the manufacturer.

1 – Blown A/C Clutch Fuse

Many times, an A/C compressor clutch fuse is to fault for a clutch failing to engage or turn on when it should have done so. However, it is necessary to discover the exact cause of the fuse’s failure as well. This can be caused by a shorted hot wire or a malfunctioning clutch assembly, among other things.

2 – A/C Clutch Relay Failure

The majority of automobiles rely on the usage of a relay to regulate the operation of the air conditioning clutch. When the relay fails or becomes stuck, it might prevent power from being transmitted to the clutch’s coil.

3 – Faulty Switches

Modern car air conditioning systems rely on the employment of a number of switches in order to function efficiently. These switches have a direct impact on the transmission of power and ground to an A/C clutch. Low pressure switches, high pressure switches, and evaporator temperature sensors are some of the more notable of these switches. The breakdown of any of these sensors can result in the inability to operate an A/C clutch.

4 – Faulty Wiring

In most situations, electricity and ground are supplied to an A/C compressor’s clutch assembly by a wiring pigtail that is connected to the engine’s main wiring harness through a connector. It is not possible for the compressor’s clutch to work if there is an open state on any of the wires in this circuit. In rare circumstances, the wire may be in good condition, but the harness may be faulty.

5 – Low Refrigerant Charge

The low pressure switch on an air conditioning system is meant to disconnect power and ground delivery to the compressor clutch in the event of low system pressure. As a result, a low refrigerant charge is frequently the cause of a failure of the compressor clutch to operate properly.

6 – High Refrigerant Charge

In a similar vein, the high pressure switch on an air conditioning system is designed to limit power and ground delivery to a compressor’s clutch in the case of an over-pressurization occurrence. If a system is overloaded with refrigerant, the high pressure switch will, by default, impair the clutch’s ability to operate.

7 – Faulty A/C Clutch

The clutch component of a compressor might begin to exhibit signs of wear and tear over time. The face of the clutch plate of an A/C clutch will wear down over time, and this will cause the clutch to slip. It is also possible for the coil of an A/C clutch assembly to break completely, preventing the clutch from engaging.

8 – Control Head/Computer Failure

Through the system’s dash-mounted control head, an A/C clutch receives its operating orders from the driver and performs the necessary operations. Any form of failure inside this device has the potential to prevent the clutch’s coil from being activated.

Several systems additionally pass control head signals through the vehicle’s ECM/PCM for additional security. As a result, a partial failure of a control module can also result in the functioning of the compressor clutch.

How to Manually Engage an A/C Compressor Clutch

There are a variety of situations in which manually engaging the clutch of an air conditioning compressor might be beneficial. Perhaps the finest application of this technique is when seeking to establish whether or not the clutch itself has failed to function properly. If you provide the clutch coil with various hot and ground sources, it will be easier to identify the source of the compressor clutch-related difficulties. The instructions below will guide you through the process of manually engaging the clutch component on your air conditioning compressor using the jump technique.

  1. Detach the Clutch Wire Pigtail:To begin, you must locate and disconnect the wiring pigtail that corresponds to the clutch assembly on your compressor. The wiring for this component is normally run from behind the air conditioning unit, near the front end of the vehicle’s compressor
  2. However, this is not always the case. To complete this task, you must first identify the power and ground wires that are present in this connection. In case of uncertainty, always refer to the manufacturer’s wiring schematic for your individual car. Make Jumper Wires:You will now need to make jumper wires for both the power and ground ends of the control circuit for your compressor’s compressor. An inline fuse must be included in the jumper wire that will be used on the positive side of the circuit if it is to function properly. It is also beneficial to attach alligator clips to the supply end of these jumper wires, so that they may be quickly linked to the terminals of your battery. It will now be necessary to connect your freshly fashioned jumper wires together in a logical manner. Please double-check that the fused jumper wire is connected between the positive wire of your clutch coil and the positive post of your battery. The remaining jumper wire should be connected by connecting it to the negative wire of the clutch coil and the negative post of your battery. You will now be able to establish whether or not your A/C clutch is defective based on the observations you have made. If your compressor’s clutch fails to engage when the compressor is jumped, it is recommended that you replace the compressor. The sudden rearward movement of the assembly’s clutch plate, which will be accompanied by an audible ‘click,’ will indicate that the clutch has engaged. If your A/C compressor’s clutch engages when jumped, further investigation will be required because the underlying fault is located in the system’s control circuit.

Replacing the A/C Compressor Clutch vs A/C Compressor

For a long time, replacing an A/C clutch was considered to be a more cost-effective option than replacing an A/C compressor in its whole. These days, however, this is not always the case. Most major automobile manufacturers now suggest that a compressor be replaced in the case of an A/C clutch failure, regardless of the brand. In reality, many of today’s A/C clutches are no longer capable of being serviced on their own. This needs the replacement of the compressor since it completely eliminates the option of clutch renewal.

In today’s market, aftermarket air conditioning compressors are available at a reasonable price, removing the financial benefit associated with clutch replacement.

Also see: Signs and Symptoms of a Faulty A/C Expansion Valve

What Should I Do If AC Compressor Clutch Is Not Engaging

In case you notice that the air conditioning (AC) compressor clutch in your automobile is not engaging, you may need to get assistance from a professional. You will discover what you can do in such a case by reading this post. It is possible that the compressor clutch is not engaging for a variety of reasons. However, you will be unable to utilize your air conditioning system during this time. The compressor clutch is a critical component of your vehicle’s air conditioning system. As a result, it is a significant annoyance for the passengers when it is rendered useless.

In some cases, even if you use synthetic oil or coolant in your car, the compressor clutch might be destroyed as a result of electrical issues.

The majority of automobiles today employ an electromagnetic air conditioning clutch system to automate the operation of engaging and disengaging the air conditioning compressor.

Because you rely on your air conditioning system to perform flawlessly, we’ll walk you through the procedures you should take in such a case. But first, let’s go over some of the fundamentals of an air conditioner compressor clutch.

What is an AC Compressor Clutch?

It is the flywheel of your car’s engine that provides the power for an air conditioning compressor clutch to operate. Using an electromagnetic switch, it is controlled by a clutch system in which the shaft of the flywheel is engaged and disengaged from a spinning shaft of the clutch system. Your car’s air conditioning system is comprised of several critical components, two of which are the compressor and clutch. These parts, as well as other automotive components, should be regularly maintained in order to guarantee that they are always in proper working order at all times.

How Does an AC Compressor Clutch Work?

The clutch compressor is triggered in order for you to be able to utilize the air conditioning in your automobile anytime you wish. The clutch compressor is powered by an engine that is directly linked to the pump rotor of the compressor by means of a belt drive. The majority of automobile air conditioning systems make use of an electromagnetic clutch element that engages the compressor in order to spin the air conditioning unit. The compressor clutch is made out of a friction plate that is placed next to an electromagnetic coil to provide friction.

This generates a powerful electromagnetic force that pulls the coil in the direction of the friction plate and contacts the pump rotor, which in turn drives the compressor to operate.

How to Determine Whether the Compressor Clutch Is Working

The pump will not operate if the clutch does not engage with the compressor. There will be no coolant or refrigerant to circulate through the air conditioning system in order to cool your vehicle if this occurs. To determine whether or not the clutch is functioning properly, use the following methods:

  • Set the air conditioning controls to the highest possible setting. Start the vehicle’s engine. Take a closer look at the front of your clutch purse. When you reach this point, the clutch and pulley should both be rotating. It is not possible for the clutch to operate when the pulley is the only spinning component.

Important pointers to remember if you are not an expert in automobile maintenance. According to Smart motorist, I recommend that you collaborate with a Car Diagnostic Tool. Most scan tools can be plugged straight into your dashboard and can even give you notifications when there is a problem with your vehicle’s electrical system. This is not only for problems with the air conditioning compressor, but for nearly all problems with the engine as a whole.

What Can Make The Clutch Not To Engage?

Some of the probable reasons why the clutch does not engage with the compressor are listed below.

  • An insufficient amount of lubricant in the compressor
  • Too much refrigerant
  • Not enough refrigerant Using the clutch sensor’s lockout as a default setting: Most current automobiles are equipped with air conditioning compressor clutches, which are controlled by the high- and low-pressure switches, as well as the amount of compressor oil, which is controlled by the fuse. This combination of three factors can prevent the clutch from engaging if the sensor detects that the compressor has inadequate oil, has too much refrigerant, or has too little refrigerant. Fuse that has been blown: To determine whether or not the fuse has been damaged, turn off the car’s engine and remove the fuse from the system. Check the fuse with a multimeter or any other instrument that can determine the fuse’s state of readiness. If the fuse has not been damaged, it should be returned to its original position.

What Should I Do If AC Compressor Clutch Is Not Engaging?

The following are some of the various methods that you might take to resolve the situation. The level of compressor oil may be easily determined by looking through the display glass. A red line in the display glass indicates that there is sufficient oil. If the level falls much below the red line, you will need to add more oil. It is essential that you choose an oil type that is appropriate with your specific compressor model. Make use of compressor oils that have been certified by the manufacturer of your air conditioning system.

See also:  Pour point and pour point depressants? (Solution)

A high pressure reading on the system indicates that the compressor has been overloaded with a refrigerant, which is not usual.

You should drain the refrigerant from the compressor if you are convinced that it has been overcharged. A discharge valve should be located near the gauge. Continue to bleed until you reach the desired degree of pressure.

The amount of coolant in the compressor should be checked to see whether it is too low by looking at the pressure gauge on the high-pressure side of the compressor. If the pressure gauge records a lower pressure than required, the compressor is too low. You can find out what degree of pressure to use in your automobile by consulting the owner’s handbook for your vehicle. Recharging your refrigerant is possible with the use of repair kits, which come with detailed instructions on how to recharge the coolant.


It is not difficult to determine whether or not your air conditioner’s compressor clutch is faulty. If you notice that anything is not operating properly with the air conditioning system, you can assess if there is a problem with it. If the DIY suggestions don’t provide the desired results, you may take the car to your technician and have him do a thorough inspection of the air conditioning system. When there is a problem with the system, the clutch on the AC compressor is not supposed to engage.

As a result, the next time the clutch fails to engage, be sure to check these components on a regular basis to avoid problems: We hope you found the information in this post useful!

Car air conditioner compressor clutch not engaging

Using the troubleshooting steps given here, you may determine if your car’s air conditioner compressor clutch is not engaging properly. The air conditioning compressor is engaged and disengaged by use of an electro-magnetic clutch, which is used by automobile manufacturers. The three components of the air conditioning compressor clutch in an automobile are as follows: When power is applied to the clutch coil, the magnetic field created by the current draws the clutch in and engages the compressor shaft.

  1. As a result, you should begin by evaluating whether or not the compressor clutch is operational.
  2. Then have a look at the compressor clutch from the front.
  3. If the only thing that is rotating is the pulley, there is an issue elsewhere in the system.
  4. In certain cars, the low pressure switch and the evaporator temperature sensor are used to control the compressor clutch relay, which is switched on and off.
  5. Remove the electrical connector from the clutch coil and set it aside.
  6. Use a digital voltmeter to check for battery voltage and good ground at the connector when the engine is running and the AC is set to the maximum setting.
  7. If the fuse is good, replace the compressor clutch relay.

Some automobile manufacturers use the PCM or ECM to trigger the relay control coil ground, while others do not.

When electricity is applied to other cars, it passes via the air conditioning switch and into the fuse, and then passes through the fuse, past the low pressure and evaporator temperature sensors, and into the clutch coil.

As a result, automakers include a low pressure switch in their vehicles, which prevents the compressor from functioning when the system is short on refrigerant.

However, if the system’s refrigerant level is too low, the clutch will not engage.


Even if you are successful in getting it to accept a charge, it is possible that you have already destroyed the compressor.

This will force the compressor to operate with insufficient oil, which may result in the compressor being destroyed.

Due to the fact that there is likely air and moisture in the system, the leak is significant and should be addressed.

After that, the system should be completely evacuated to ensure that all air has been removed before it can be recharged.

Adding extra refrigerant is possible without having to hot wire the low pressure switch and operate the compressor at full capacity.

In order to recharge the battery, connect it to the low pressure (suction) connector.

In addition, the DIY kit fitting will only attach to the low pressure port, not the high pressure.

To activate the radiator fans, turn the air conditioner up to its maximum setting.

Depending on whether your car is equipped with an orifice tube system, the refrigerant gas will pass through one of the open compressor reed valves before entering the condenser coil.

Because the compressor will not be functioning, there will be no pressure in the system.

Whenever a liquid enters the evaporator, it will boil and change back into a gas as long as the blower fan is operating.

Try starting the engine and inspecting the compressor to see what happens.

If this procedure does not work, you should take it to a professional.

Compressor and clutch assembly for air conditioning systems Sachin was founded in 2015.

Technical service bulletins, code definitions and step-by-step testing, as well as easy-to-understand wiring diagrams, are all included, as is an explanation of how the systems are designed to function.

Take a look at these!

Furthermore, you must access to the most recent technical service bulletins so that you do not spend time and money repairing parts that may misbehave as a result of a software bug on the part of the manufacturer.

They will only serve to mislead you.

Get a 1-Month (31 Days) subscription for $16.99, a 1-Year (Best Value!) subscription for $25.99, or a 4-Year (Best Value!) subscription for $39.99. I like the wiring diagrams on to the difficult-to-read factory schematics on Alldatadiy because they are more user-friendly.

A/C compressor clutch not engaging

The troubleshooting strategies discussed here can be used to resolve a scenario in which your car’s air conditioner compressor clutch fails to engage. In order to activate and disengage the air conditioning compressor, automobile manufacturers utilize an electro-magnetic clutch. A car’s air conditioning compressor clutch is made up of three parts. Because of the magnetic field created by power energized clutch coil, it is pulled into engagement with the compressor shaft when power is supplied to it.

  1. Determine whether or not the compressor clutch is operational before proceeding with your diagnosis.
  2. Then have a look at the compressor clutch’s front end.
  3. It is likely that a fault exists elsewhere in the system if just the pulley turns.
  4. When the low pressure switch and the evaporator temperature sensor are activated, the compressor clutch relay is switched on and off in some automobiles.
  5. Unplug the clutch coil’s electrical connector from its socket.
  6. Use a digital voltmeter to check for battery voltage and good ground at the connector when the engine is running and the air conditioning is set to the maximum.
  7. Ensure that the fuse is in good working order before pulling the compressor clutch relay and checking for power and ground on both the control coil terminals and on the relay control coil terminals in the socket.

Some automobile manufacturers use the PCM or ECM to activate the relay control coil ground.

When electricity is applied to other cars, it passes via the air conditioning switch and into the fuse, and then passes through the fuse and into the clutch coil through the low pressure and evaporator temperature sensors.

To keep the compressor from functioning when the system’s refrigerant level is low, auto manufacturers include low pressure switches.

It will never engage, though, if the system is running low on refrigerant.

WASTE OF TIME AND ENERGY The compressor is being used with little to no oil at this stage.

Under no circumstances should you attempt to circumvent the low pressure switch.

It is theoretically impossible to recharge an air conditioning system using a DIY kit if the system’s refrigerant level is low enough to release the compressor clutch.

Because of the way moisture combines with the refrigerant and oil, it produces acid and sludge, which can cause the system to fail completely.

Fortunately, I’m astute enough to realize that you’re unlikely to do so.

This approach is provided with the understanding that I will not be held liable for any harm you may do.

A bigger diameter is always present in the low pressure tubing as compared to that of the high pressure line.

Turn the ignition key to the RUN position and the blower fan to the HIGH setting before starting the vehicle.

Begin by adding refrigerant to the system.

With the help of the radiator fans, the refrigerant will condense and revert to its liquid state again.

However, there is a good probability that some of it will make it to the orifice tube and flow into the evaporator coil nonetheless.

After a few minutes, you may be able to build up enough pressure to close the low pressure switch on your thermostat.

For systems with expansion valves, the blower fan will keep the detecting tube from shutting off the expansion valve while you are adding refrigerant to the system.

Hot wiring the low pressure switch is strictly prohibited. was founded in 2015 by Sachin Naire Professional-quality shop manuals are available from Eautorepair at no additional cost.

Everything will be provided at a cost that is affordable.

To work on a late-model car, you’ll need a professional shop handbook.

Do not rely on the low-cost manuals you might get from your local auto parts store.

With a consumer-style interface, is actually Mitchell On Demand.

For $16.99, you may get a 1-month (31-day) membership, a 1-year (the best value!) subscription for $25.99, or a 4-year (also the best value!) subscription for $39.99! Better than Alldatadiy’s difficult-to-read factory schematics are the wiring diagrams on, which I prefer.

How To Manually Engage AC Compressor Clutch: The Easiest Methods

Tsukasa Azuma is the author of this piece. Comments received since the last update on December 24, 20200 Many major problems can arise in a car, and one of these is a malfunctioning air conditioning compressor clutch. When this component is not functioning properly, the engine does not receive sufficient cold air flow, which might result in some serious issues. Knowing how to manually engage the AC compressor clutchcan save you money by avoiding a trip to the mechanic’s shop. In addition, you should be familiar with how to inspect the clutch to determine if it is malfunctioning or not.

How To Examine The AC Compressor Clutch?

Failure of an air conditioning compressor clutch may result from the use of low-quality oil, but it may also occur even if you use synthetic oil and high-quality coolant. It has been reported that the clutch does not engage in a few instances owing to a blocked refrigerant circuit. If you wish to check for problems with an air conditioning compressor clutch, use the following techniques:

Working Method 1

Before starting the engine, make sure all of the air conditioning settings are set to the maximum setting. Examine the condition of the clutch’s front side to determine its age. Additionally, check to see whether the clutch and pulley are rotating. It is possible that the compressor clutch is experiencing a problem if just the pulley is turning. The problem might be caused by a blown fuse, poor clutch oil, low-pressure lockout, or an open wire embedded in the oil, among other things. Before examining the compressor, turn the air conditioner up to its maximum setting.

Working Method 2

In some automobile models, a low-pressure switch might cause difficulties with the compressor clutch’s relay, which you should be aware of before moving on to the next phase of the diagnostic process. The relay is grounded by the system’s computer, but it is susceptible to being turned on and off by a faulty switch. An in-depth examination of the system and its components can assist you in identifying the root of the malfunction. It is necessary to disconnect the connection cable from the clutch oil at this phase.

Make use of a digital voltmeter to check the ground and battery voltage at the end of the disconnected connection cable.

If the fuse is found to be in working order, proceed to the clutch relay.

Working Method 3

When the air conditioning system is turned on, electrical power travels from the AC switch to a fuse before being passed to the clutch oil through a temperature differential between the low-pressure evaporator and the clutch oil. This means you must make certain that the compressor has sufficient oil to perform correctly. The next step is to engage the clutch after you have determined that there is an issue with it. The next section explains how to manually activate the AC compressor clutch at your house.

  • The Simplest Method for Using a Recharge Kit for Your Car’s Air Conditioning
  • Do you want to recharge your car’s air conditioning system at home? Take a look at this

How To Manually Engage AC Compressor Clutch

It’s not difficult to engage the AC compressor clutch at home; it’s not rocket science.

There are a handful of ways you may resolve the issue in order to restore proper operation to the air conditioning system.

Method 1: Add More Coolant

In what situation does an air conditioning compressor fail to activate the most frequently seen reason? There is a low level of refrigerant. When the amount of coolant in the system drops below a certain point, the low-pressure switch prevents the compressor from rotating. When the system’s antifreeze level is low, how do you manually activate the AC compressor clutch? Easy. Simply increasing the amount of refrigerant will solve the problem. It is possible to restore the normal working of the compressor clutch by adding a can of R134a refrigerant to your car’s system if it is compatible with this type of refrigerant and the low-pressure switch has been disabled.

Inadequate lubrication has the potential to cause harm to the compressor.


Method 2: Jump-start The Clutch

For older vehicles that are not compatible with the R134a type, the procedure is a little more complicated. Only a few minutes are required to get things going, and the procedure will not last longer than that: Check the oil level in the compressor to make sure it is enough. If the level is below the typical point, more oil should be added. Check the owner’s handbook to ensure that you are following the recommended procedures for monitoring the compressor oil level and refilling the compressor.

Take the fused jumper wire and attach one end of it to the side of the wire connector that was connected to the compressor, and the other end to the other side of the wire connection that was not connected to the compressor.

Remove the jumper wire from the battery.

It is not necessary to turn on the air conditioning system in order for this approach to function.

Method 3: Replacing The Clutch

When the clutch engages but the compressor does not spin, it is a warning indication that something is wrong. In this situation, it is possible that changing the compressor clutch is the only option. A faulty AC compressor clutch must be repaired as soon as possible. In the event of a delay, substantial damage to the air conditioning system and engine may result.

Diagnose Car AC Clutch Wont Engage Problems

The Car’s Air Conditioning Clutch Will Not Engage When the car’s air conditioning clutch refuses to engage, you switch on the air conditioning and patiently wait for cold air that never arrives. When you turned on the air conditioning from the control panel, you undoubtedly felt something a bit different. When the compressor kicks in, you’ll frequently hear a click and feel the engine struggle to keep up with the additional strain on the compressor. Manufacturers try everything they can to conceal both of these signs of a fully functioning air-conditioning system, but it is impossible.

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When you open the hood of your car with the highest air conditioning turned on, you may frequently discover that the car’s air conditioning clutch is not engaged.

That front plate is connected to the compressor driveshaft and must be engaged against the pulley in order for the compressor to work. We’ll go through some of the most typical reasons why an automobile’s air conditioning clutch fails to function correctly.

Proper Car AC Clutch Operation

Car Air Conditioning Compressor Clutch Diagram In order to find out what is wrong with the car’s air conditioning system, we must first understand what happens when the compressor is activated from the AC climate control panel on the dashboard. To activate the compressor, as you can see from the image on the right, we have three independent elements that must all work together in the proper manner. The compressor clutch assembly is located at the front of the vehicle and connects to the driveshaft.

The innermost component is a strong electromagnet, which pushes the clutch against the rotating pulley as the clutch is engaged and released.

This results in the production of an audible click sound.

Because of this, it is important to open the hood and have a buddy switch on and off the air conditioning to visually check whether or not the clutch is locked in place.

Where to Start AC Clutch Diagnosis

When I come across an AC clutch that isn’t engaging, the first thing I look for is the electrical connector that connects to the compressor. The compressor for the air conditioning system creates a lot of heat and vibration. All too frequently, this potent mix can take its toll on the electrical connection that is used to transmit the signal. You may even try wiggling the connector to see whether the AC clutch is activated by wriggling the connector. The next step is to check that there is electricity and a good ground present.

  1. It should be noted that in a one-wire system, the electromagnetic coil is grounded through a case ground.
  2. If you have a 12 V request signal as well as a good ground, the problem is most likely in the compressor section of the system.
  3. Nonetheless, a small number of autos are prone to malfunctions in this region.
  4. More information about Honda VTEC difficulties may be found here.

In fact, because of the high demand for compressors, replacement parts for these devices are available at cheap costs. When the compressor fails to kick on, it is more probable that there is a lack of AC requestsignal at the compressor connector, than than the other way around.

Common Problems with the AC Request Signal

Low Refrigerant Pressure Switch on an Air Conditioning System As previously discussed in the first phase of diagnosis, the most common reason for the compressor failing to turn on is due to the compressor not getting a power signal. Despite the fact that the list of likely reasons is incredibly large, we are lucky in that a few frequent difficulties account for more than 75% of the concerns. Let me begin by stating the most optimistic situation. Automobiles that are becoming older will have problems with the air conditioning relay failing more frequently.

  • It’s important to note that this is slightly model specific.
  • I have a full post on how to test the car’s air conditioning relay and I hope this accurately depicts your situation.
  • With an affordable air conditioning service, you can find out how much Freon is still in the system and make the necessary adjustments.
  • If the Freon seeps out, the lubricant also leaks out.
  • It is possible for these pressure sensitive switches to fail.
  • That is something you should never do.
  • Furthermore, simply turning it on can be devastating.
  • In order to address this issue, a set of air-conditioning manifold gauges should be connected to both the high and low pressure test ports.
  • Many people will simply toss in a can of Freon and hope that the system will continue to function for a long.
  • The length of time it takes for the recharge to complete becomes an indication of the severity of the leak.
  • This is another another topic that I went into great detail about.

Uncommon AC Compressor Clutch Problems

There are certain automobile manufacturers who are far too clever for their own advantage. Take a difficult system and make it even more complicated by adding more variables. These automobile manufacturers transmit an AC request signal to the vehicle’s main computer. Despite the fact that the reasoning behind it is still true, the actual implementation is a weak link in the chain. In other words, a faulty ECM might result in the air conditioning system failing to function. A request signal for air conditioning has also been included in certain vehicles, which is generated by the temperature control panel or body computers.

Please see the following link for an article about Chevrolet computer faults that prevent the air conditioning from turning on.

In addition, we go into much greater depth on repairing ancient automotive air-conditioning systems and the usual issues that arise as a result of them.

For those who are interested in other automotive themes, the fix my old vehicle homepage is a good place to begin your search. Because I am an Amazon Associate, I receive money when people make eligible purchases.

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Car AC Compressor Won’t Turn On? 8 Reasons and Solutions

As an Amazon Associate, receives a percentage of the sales made via our links. When you turn on the air conditioning in your car and you still get pelted with hot air, it’s quite inconvenient. This is enough to drive you mad on a hot summer day in the South throughout the summer. When the air conditioner compressor does not come on, the most typical cause is a lack of refrigerant in the system. If there is a leak, no matter how tiny, it will eventually result in the inability to operate the air conditioning system.

If you don’t know where to look, your owner’s handbook should be able to direct you.

The good news is that The hot air that is flowing from your vents is not a death sentence for your automobile.

In this tutorial, we’ll go through the top eight reasons why your car’s air conditioning compressor isn’t working, as well as some possible fixes for each issue.

What Is an AC Compressor?

When it comes to your car’s HVAC system, the compressor is only one component. It’s surprising how many people don’t give any thought to how frigid air is forced through your car’s vents, even when the temperature outside is above 100 degrees. It takes a little bit of magic and a whole lot of science to do this. Most of the time, the A/C compressor will be located in front of the engine, among the other belt-driven devices. As you drive, the air in your automobile is drawn in from the outside.

  • As a result, what happened?
  • One of the most significant causes is your air conditioning compressor.
  • The compressor is responsible for moving the refrigerant around.
  • It is the primary function of the air conditioning system in the automobile cabin to remove heat from the cabin, with the compressor and clutch plate equipment being utilized to get it up and running.

8 Reasons Why Your Car AC Compressor Won’t Turn On (and Solutions)

There are a variety of reasons why your air conditioning compressor may be malfunctioning.

The remedy to each of the reasons is a bit different. Let’s take a moment to go through each of the eight possible reasons why your car’s air conditioning compressor isn’t working.

Low Refrigerant in the AC System

This is by far the most common reason for your air conditioner not to function properly. AC pressure sensor switches will detect low levels of AC freon refrigerant, which will prevent the AC from kicking on. The R134a refrigerant is the most commonly used refrigerant in today’s world. In order to determine the state of the pressure, two conditions must be examined. As can be seen in the image below, the low-pressure side is represented by the color blue, while the high-pressure side is represented by the color red.

  1. At 75 degrees outside temperature and 30-40 PSI, the pressure should be in the low 30s to 40s.
  2. On the high-pressure side, the PSI should be twice as high as the ambient temperature to ensure proper operation.
  3. Solution: After checking the AC for the quantity of PSI in both the low and high-pressure lines, re-fill the AC and carefully watch the gauges for any changes.
  4. A dye can be used to detect the presence of an AC refrigerant leak while re-filling the system, such that the next time it stops operating, the dye will be visible when checking the system in the dark with an ultraviolet light.
  5. I would recommend beginning at the A/C compressor and working your way down the A/C lines, paying close attention to every detail.

A Faulty Car AC Pressure Sensor Switch

Occasionally, when you turn the dial on your center console to the ‘cold’ position and nothing occurs, it might be because your temperature control switch has failed. This switch changes the temperature of your HVAC system from hot to cold. If the switch is not functioning properly, your vehicle’s HVAC system will be stuck on one of the two settings it has. In your scenario, the heat setting has been stuck. You might have a perfectly good compressor; it’s simply that it’s not getting the signal to cool things down.

Your best chance is to try some of the other suggestions on this page, and if it doesn’t work, then you should consider replacing this temperature control switch.

Switch with an alternating current pressure sensor

Relay or Fuse Problem

Capacitors and relays are little electronic components that are integrated into the wiring of your vehicle. We won’t bore you with the technical details of how these components work, but we should point you that they are very necessary. It is possible that the whole voltage will not reach its destination if the relay or capacitor has a problem during its operation.

If all of the electricity does not make it to your compressor, it will not be able to operate. Solution: Inspect the capacitor and fuses for the air conditioner and replace them if they appear to be worn or broken. Close-up of the fuse box of a car. Multiple rows of fuses and relays of varying types

Compressor is Dead

The basic reality of the matter is that the compressor can go out of commission at any time. It’s possible that a component within it has failed, rendering it inoperable. Once a compressor has failed, the only option is to replace it entirely with another one. You don’t have to take it to a mechanic if you can do this on your own. In the event that you decide to take on this project, expect to spend a few hundred dollars on parts. Replacement of the compressor is the solution. Inside the engine compartment, the A/C compressor is fixed to the engine and has a belt attached.

It’s Not Getting Power

Before the compressor can be turned on, it must be supplied with electricity. If this were not the case, your air conditioning would continue to run even when the automobile was switched off. In other words, if the vehicle’s voltage is low, it might have an impact on the electronic modules that are responsible for the air conditioning system. Once the car is started, the alternator will maintain a consistent voltage, although there may still be some error messages shown on the dashboard. Troubleshooting your battery is the solution.

Check to see whether your car can be jumped or if the battery has to be replaced.

Wiring Issue

The use of faulty wiring is yet another electrical problem that might occur. This does not imply that the compressor maker acted improperly; rather, it indicates that something went wrong somewhere along the line. Alternatively, if your compressor has never operated, it might be because the internal wiring were not appropriately placed. If you installed the compressor yourself, double-check that the cables were routed correctly before proceeding. If this problem began to occur at random, you may be able to credit mice for your troubles.

You’re left with a jumble of disjointed components strewn over the space.

Visually check the A/C wire that runs from and to the A/C components (fan clutch, compressor, fuse/relay) in the engine bay to the opposite side of the firewall, where the ECU/BCM and climate control are located.

Wiring can become corroded, damaged, or entirely cut at any point in time.

Compressor Clutch Isn’t Engaging

When the compressor is turned on, the shaft of the compressor will begin to revolve. There’s a little clutch that is pressed against the shaft and engages the mechanism. Once the clutch is engaged, the air will begin to cool as soon as the clutch is released. Because if the clutch isn’t engaged, the compressor will merely spin freely with no reaction from the engine. There is a straightforward solution to this problem. Make sure your car’s HVAC system is set to ‘heat’ in order to blow hot air.

You should be able to tell that the disk on the pulley side of your compressor is completely still.

Get in your car and switch on the air conditioning before returning to the front of your vehicle. Check to check if the clutch is moving at this point in time. Solution: Inspect the connections on the clutch and, if necessary, replace the clutch if it has suffered mechanical damage.

Rusted Clutch Plate

Begin by stating that rust on some portions of your clutch plate will not result in the failure of your air compressor. The substance in question is really a byproduct of a compressor that has seen better days. Alternatively, rust on the clutch’s outer ring might be the source of the problem. In either instance, if you notice rust, it might be an indication that your compressor has died as a result of its age. Solution: Replace the clutch plate, which may need the replacement of the compressor as well.

Prevent a Dead AC Compressor in the Future

As you can see, troubleshooting an AC compressor that won’t switch on entails a significant amount of investigation. If you want to avoid this time-consuming troubleshooting, you need be aware of how to avoid this problem in the first place. The most important method of prevention is routine maintenance. You may want to get your air conditioning system serviced by an auto shop every spring so that you can stay ahead of the problem. A manometer is used by a mechanic to check the performance of the vehicle’s air conditioning compressor.

By investing a little time and money today on upkeep, you will be able to save a significant amount later.


We hope you are able to identify the source of your AC compressor’s failure to switch on. Our eight explanations and remedies should assist you in narrowing down the problem and troubleshooting your way through it. Visit our blog for additional information about auto maintenance. Make certain that you have the appropriate accessories and equipment to make your life simpler.

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