How turn signal flasher works? (Solution)

  • When either a left or right turn signal is selected, the flasher electrically connects to the signal bulbs on the car, completing the circuit. The current flows through the resistance wire, causing it to heat the spring steel around which it is wrapped. In a brief period, the spring steel expands, straightening out the larger piece of spring steel.

How do turn signal flasher works explain its operation?

When you push the turn-signal stalk down, the thermal flasher connects to the turn-signal bulbs by way of the turn-signal switch. This completes the circuit, allowing current to flow. Initially, the spring steel does not touch the contact, so the only thing that draws power is the resistor.

How does a 3 pin turn signal flasher work?

The heart of the flasher is the relay. The relay is the electromechanical device that makes the operator switch-selections happen. Typically, a switch is engaged, which energizes the electromagnet in the relay. This electromagnet closes contacts that power the flasher and lighting circuit.

How does a 4 pin flasher relay work?

4 pin relays use 2 pins (85 & 86) to control the coil and 2 pins (30 & 87) which switch power on a single circuit. There are 2 types of 4 pin relay available; normally open or normally closed. A normally open relay will switch power ON for a circuit when the coil is activated.

How do turn signals make noise?

When you turn the signal on, a current is sent through the bimetallic spring that heats it up. The two metals within the spring heat up at different rates, forcing them to bend in a certain way. There are no moving parts, which means no bimetallic spring, yet they still make that clicking sound.

How do you test a 3 pin flasher relay?

How to Test a Three-Prong Flasher Relay

  1. Identify the terminals.
  2. Clip the test light lead between the ‘P’ terminal and the negative terminal of the battery.
  3. Connect the ‘B’ terminal to the positive terminal of the battery using the test wire with equal-length stripped ends, with one clip on each end.

Will LED flasher work with regular bulbs?

Compatibility: All LED flashers from CEC, including the Solid State flashers, are compatible for use with regular bulbs as well as LED bulbs or a mix of LED / regular bulbs. There are many cheap LED flashers on the market that will simply go up in smoke when you put regular bulbs in.

How do I know if my turn signal flasher is bad?

The most common symptom of a bad or failing turn signal / hazard flasher is hazards or turn signal lights that do not function. If the flasher breaks or has any internal issues it can cause the lights to malfunction, or not respond at all when the turn signal lever or hazard light button are pressed.

Why does turn signal fuse keep blowing?

If the blower and turn signal issues started at the same time its very likely there is a short in the wiring harness somewhere. When shorts occur they will blow the fuse as the circuit is getting too much power.

How do you know if your turn signal switch is bad?

Symptoms of a Bad or Failing Turn Signal Switch

  1. Turn signal indicator continues to blink when the steering wheel returns to the center.
  2. Turn signal lights don’t continue flashing unless turn signal lever is held down.
  3. Left or right turn signals or the Hazard Warning Light not working properly.

What color is the turn signal wire?

The red wire is the turn signal wire and will be run to the green wire of your harness if its the right turn signal side, and the black wire will run to the brown wire of your harness.

How Turn Signals Work

When the automobile is not in use, this compact, cylindrical gadget is occasionally seen in the fuse panel under the dashboard. It costs around $3 at a local auto parts store and has been reliable for years. There are only a few simple components in the thermal flasher’s interior:

  • Electricity is conducted into the wire through an electrical contact. A piece of spring steel with a gentle curvature to it to which the electrical contact is attached
  • Aresistive wire is wrapped around a tiny piece of spring steel to provide resistance.

When you depress the turn-signal stalk, the thermal flasher is activated and communicates with the turn-signal bulbs through the turn-signal switch. When this happens, the circuit is complete, and current can begin to flow. The spring steel does not make contact with the contacts at first, and as a result, the only object that drains power is the resistor. When the current passes through the resistive wire, it heats up the smaller piece of spring steel before going on to the turn-signal lights.

It takes less than a second for the little piece of spring steel to heat up sufficiently to the point where it expands and straightens out the bigger, bent piece of spring steel.

When there is practically no current flowing through the resistor, the spring steel quickly cools, bending back away from the contact and completing the circuit by breaking it.

This occurs one to two times every second at a pace of one to two per second.

How turn signal flasher works

Many people are curious in the operation of the older mechanical (or thermal) turn signal flasher. Turn signal lamps are powered by mechanical switches that use a bi-metallic strip of metal and a heater to transfer electricity to the turn signal bulbs. These are referred to as thermal flashers since they rely on a heater and a bi-metallic strip in order to function properly.

Also interesting

How an electronic turn signal flasher works

Late-model vehicles are equipped with an electronic flasher that does not require any mechanical parts. Turn signal bulbs are illuminated by a flasher, which measures how much electricity is flowing through them. An electronic timing system and a transistor are used to switch on and off the electricity to the turn signal lamps when the current draw falls within a reasonable range. As a reminder to the driver that the turn signals are in operation, an audible clicking sound is generated by the electronic flasher, which mimics that of the earlier mechanical devices.

How a thermal turn signal flasher works

When not in use, the bi-metallic strip has an electrical contact and is fashioned in a slightly bent manner when not in use. When you switch on your turn signals, electricity travels through the heater in the turn signal as well as through the turn signal bulbs in the turn signal housing. Because the heater is a wire with a very high resistance, the current flow to the bulbs is insufficient to illuminate them. The current flowing through the heater, on the other hand, is sufficient to heat the bi-metallic strip.

When the contacts make contact with each other, a full current is sent to the turn signal bulbs, causing them to illuminate.

As long as they’re lighted, current bypasses the heater, which causes the bi-metallic strip to cool as a result of the current bypass. After cooling, it ‘snaps’ back into its original curved shape. When you snap your fingers together, you will hear a click.

What causes turn signals to flash fast?

The mechanical flasher cools more quickly and snaps back to its normal shape faster when a turn signal bulb burns out because less current travels through the mechanical flasher when the bulb burns out. As a result, even if only one bulb is burned out, the on/off cycle is significantly accelerated. Electronic flashers operate in a manner similar to mechanical flashers in that they flash at a quicker rate when they detect a decreased current flow, such as that caused by a burned out bulb. Rick Muscoplat has a new year’s resolution.

Thermal Flasher

Automobile turn-signal indicators (often referred to by their other names, blinkers or flashers) are possibly one of the most important safety measures on the road today. Turn signals, as well as danger or warning flashers, are all examples of how automotive flashers are employed. They aid in the communication of a driver’s intentions or activities to other drivers and pedestrians in their immediate vicinity. The thermal flasher is the most frequent type of turn-signal indication used in older model automotive applications, but solid state flashers are more commonly employed in later model automotive applications.

What Is a Thermal Flasher?

The thermal flasher is a tiny circular cylinder that may be found in the fuse box of a car. It is a low-cost component that is produced in the following manner:

  • When an electrical contact is made, the passage of electrical current into the flasher is allowed to occur. a bent piece of spring steel to which this contact is attached A resistive wire is wrapped around another piece of spring steel to provide resistance.

How It Works

Despite the fact that everything happens immediately, an intricate process is taking place within a thermal flasher. The thermal flasher is activated by pressing the turn signal bar or the hazard lights switch on the instrument panel. The process begins with the initiation of a sequence of reactions.

  • The circuit is completed when the turn-signal bar on the automobile is pushed down or raised up, allowing electricity to pass through the flasher to the bulbs in the turn-signal lights and out the other side. For a brief moment, the current just passes via the resistive wire and on to the signal bulbs, without coming into touch with the spring steel or contact. In fact, the current flow is so little that it is insufficient to produce even a faint glow in the bulb. Because of the resistance to the current, the spring steel heats up, expands, and makes contact with the turn-signal bulb, allowing the necessary current to pass through it to illuminate it. It takes just a few seconds for the spring steel to cool down, halting the current flow and causing the turn-signal bulb to stop shining. The rapid heating and cooling occurring within the thermal flasher causes the turn-signal bulb to flash one or two times per second, depending on the temperature. In order for the turn-signal to work, the spring steel must come into contact with the contact when the circuit is completed, resulting in a clicking sound.

What Is a Solid-State Flasher?

Late-model automobiles make more use of digital technology, including the addition of solid-state flashers to the list of electronic components controlled by computer chips. When the turn signal or hazard lights are activated in a vehicle equipped with a solid-state flasher, the current generated passes via a timing chip. Transistor-based control of current flow through the timing chip is accomplished by the utilization of current flow to activate, interrupt, and re-initiate current flow to the turn-signal bulbs.

Additionally, solid-state flashers imitate the clicking sound made by a thermal flasher in order to offer an audible indication to the driver, in addition to replicating the flashing function.

Flashers from Amperite

The replacement flashers available from Amperite are suitable for both early and late-model automobiles. Our extensive expertise and experience with flashers, sequential relays, and other associated components ensures that we will be able to assist customers in selecting the most appropriate flasher type for their application. Contact us and enable the Amperite experts to assist you in selecting the most appropriate thermal or solid-state flasher for your vehicle’s needs.

How Does a Three Pin Flasher Relay Work?

Image courtesy of Jupiterimages/Polka Dot/Getty Images In most vehicles made since the late 1930s, a three-pin flasher relay operates according to electromechanics principles to power the turn and warning signals as needed.

Turn signal systems have progressed through the ages from mechanical relays and mechanisms to solid state devices. When connected in the proper manner, all flasher relays produce an audible and visual output.

Power Demands

A flasher relay is supplied by the 12-volt direct current (DC) primary power supply of the car. It is grounded (either positively or negatively) in order to be consistent with the rest of the vehicle’s electrical system. Its circuit is intended to handle a maximum current demand, which is just sufficient to power the turn and emergency signals. Any additional demand or overload will cause a circuit breaker to trip, or a fuse or fusible link to be blown.


The relay is at the heart of the flasher’s operation. In electromechanical terms, the relay is the electromechanical mechanism that causes the operator switch selections to take place. Typically, a switch is pressed, which activates the electromagnet in the relay, causing it to operate. This electromagnet blocks the connectors that supply power to the flasher and lighting circuits of the vehicle. It is possible to pick the left, right, or both sides.

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The flasher is a thermostatic switch that is programmed to turn on and off at a predetermined rate. Depending on the application, flashers are often programmed to operate at 6 or 12 volts. The flasher is a full device that is not normally intended for use in a service environment. BibliographyWriter’s Bio Currently employed as a school district administrator, Jennifer Ramirez has more than ten years of experience as a tax expert. She has a wealth of knowledge and expertise in the fields of mathematics and physics, and she writes a blog on cuisine and environmentally friendly living.

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Turn signals are something that everyone takes for granted. They provide an essential safety advantage, of course, and they seldom fail to function – with the exception of a few burned bulb filaments. Even though turn signal circuits are a miracle of streamlined electrical architecture, many people are perplexed by the wire that goes into them. Apart from the wires, the complete circuit is made up of the following components, which we will go through one by one:

  • The Flasher
  • The turn signal switch
  • Single or dual filament lamps at the body corners
  • Indicator bulbs on the dash
  • And the turn signal switch Emergency (all bulbs) flasher switch (on automobiles later than 1965)
  • Grounding electrically

The Flasher

The basic turn signal circuit begins at the flasher, not at the switch, as shown in the diagram. An electrical contact is located within the assembly, and it is this contact that allows electricity to flow into the flasher from the fuse panel. An electrical contact is connected to a piece of curved spring steel that is bent in half. Following that, a piece of resistance wire is wrapped around a smaller piece of spring steel that is placed next to the bigger piece of spring steel. You attach the flasher to the signal bulbs on the automobile when you choose either a left or a right turn signal, depending on your preference.

It takes just a very short length of time for the spring steel to expand, which straightens out the bigger piece of spring steel.

Without a doubt, the bulbs are turned on, and the spring steel is rapidly cooled after they are.

It curls away from the contact, breaking it and shutting off the bulb filaments in the process. The current then returns to the resistance wire, re-starting the entire process from the beginning again. Because the spring steel is bouncing back and forth, the clicking sounds you hear is normal.

Turn Signal Switch

The stalk on your steering column is nothing more than a toggle switch that changes the switch contacts to the right position for signalling a turn when you press the turn signal button on your dashboard. Because there are so many alternative designs available, we will not go into detail on how the switch assembly is mechanically engineered to be ‘self canceling.’ We’ll concentrate on the electrical operation for the time being. The switch is responsible for delivering current from the flasher (through a wire, of course) to the switch’s central contact.

The stalk is depressed to pick a left turn, and the switch’s central contact rotates up to make contact with the wires going to the left front and rear indicator lamps as well as the dash indication bulbs.

When this occurs, the filaments continue to light until the internal contact of the flasher is broken, at which point they are turned off.

Dual Filaments

The turn signal lights on the front of the vehicle are also commonly used as ‘parking’ or ‘running’ lights. The fixtures are therefore intended to work at two distinct degrees of brightness as a result of this. For the turn signal, a high brightness is required, whereas a lesser brightness is required for the running lamp. Rather than having two bulbs — or two fittings — the makers developed dual-filament bulbs a long time ago to save money. These bulbs are simply constructed of two filaments, with one filament being brighter than the other.

The current supplied by the turn signal switch flows down a dedicated wire to the bright filament, while the current supplied by the running light is supplied by a separate wire that runs from the light switch.

It is customary for the bright filament to be shared by both the brake lights and the turn signals.

Emergency Flasher

The emergency flasher (found on automobiles manufactured after 1965) is not technically an extra flasher. What it really is, however, is an override switch that’s been built in such a manner that it can override the turn signal switch and send electricity to both sides of the vehicle’s signal system, as well as its indicator lamps in the dash. It makes use of the flasher that is already in place. data-matched-content-ui-type=’image card stacked’ data-matched-content-rows-num=’3′ data-matched-content-columns-num=’1′ data-ad-format=’autorelaxed’ data-matched-content-columns-num=’1′ data-matched-content-columns-num=’1′ data-matched-content-columns-num=’1′ data-matched-content-columns-num=’1′ data-matched-content-columns-num=’1′ data-matched-content-columns

Turn sugnal Flasher Unit

The MGA With An AttitudeTURN SIGNAL – FLASHER UNIT – ET-104’I’m having some trouble figuring out why my turn signals don’t flash. Is there a way to test the flasher unit before fiddling with other things? And just out of curiosity, how does the flasher unit work?’The flasher unit is the metal can shown in the picture on the right.Click for larger picture (and yes I know there’s a wire loose).It has three screw terminals, ‘B’ for Battery, ‘L’ for Load, and ‘P’ for Panel (dash indicator lamp).If the terminals are not marked you can check it with a test light or ohm meter.The ‘P’ terminal will be open circuit at rest, and the other two terminals are functionally interchangeable.The canister does not need to be grounded, but it does need to have the correct electrical load to operate properly.And yes, you can test it by itself, but you do need to use the correct electrical load for the test.The flasher only works properly when it is driving two 21 watt lamps in parallel (for the turn signals of course).This 42 watts is a load circuit with (nominally) 3.43 ohms resistance (6.86 ohms for each operating bulb with hot filament).If you want to use a resistor to emulate the electrical load for testing, you will need a 25 watt power resistor with any resistance value within about 10% of 3.43 ohms (within the range of 3.1 to 3.8 ohms).The 25 watt resistor is large enough, because the operation of the flasher is only about 50% duty cycle for the load.If you don’t have the (expensive) power resistor handy, and don’t want to buy one, you can hook up a pair of 21 watt bulbs in parallel, either in lamp sockets or by soldering wires to the bulb contacts.Or if you have enough confidence in your car’s wiring integrity, you can just connect any two of the 21 watt bulbs in the car.To test the flasher unit, do the following:a.)Connect a hot wire (12 volts) to the ‘B’ terminal of the flasher unit.In the car you might just switch on the ignition and use a test light to verify that power is connected to the flasher in the car. If you expect to do more than a few minutes of testing in the car, you should disconnect the ignition coil to avoid overheating and possibly damaging it.b.)Connect the load (resistor or lamps) between the ‘L’ terminal and ground (return to the earth terminal of the power supply or battery).In the car you can use any handy ground point on the car.c.)Connect a grounded test lamp to the ‘P’ terminal on the flasher unit.With power and load connected, the flasher unit should commence clicking loudly on/off about one cycle per second (as you would want the turn signals to flash).If you have lamps connected for the load, the lamps should flash, and the lamps will get hot with about 10.5 watts of heat each at 50% on/off duty cycle.Using a resistor for load, the resistor will start to get hot with about 21 watts of heat (at 50% duty cycle of the flasher unit).The test lamp should also flash on/off in unison with the clicking. If it clicks at about the right rate, and the test lamp also flashes, then the flasher unit is in good operating condition.It does not hurt the flasher unit to leave it connected and operating for an extended period of time.If the flasher unit doesn’t click at the right rate, or the pilot lamp doesn’t flash, then the unit is considered trash and needs replacement, because it’s a sealed unit and generally non-repairable.If you were the curious type you could pry it open to see what’s inside (nothing to lose but your time).For a non-working pilot lamp you might be able to clean the contacts.For a non-clicking unit you might have to rewind the heater element wire, which is beyond the scope of these test instructions, and also probably not cost effective.End of test.Beyond that, if you understand how the flasher unit works, you may better understand some of the flasher quirks you may encounter from time in your car, and might be better equipped to repair the other problems.Inside the flasher unit is a bimetal strip that will bend when heated.It is mounted in such a manner as to snap suddenly (and loudly) over center when heated or allowed to cool. This sudden change of position makes or breaks a relay contact to cause the turn signal lamps to flash.There is a winding of heater wire wrapped around that bimetal strip.One end is connected to the system power terminal ‘B’, and the other end is connected to the output terminal ‘L’ (going to the load).Passing a small current (less than one amp) through this heater wire causes it to heat up (about 7 watts of heat) and in turn heat the bimetal strip to make it bend and snap into the alternating position.Otherwise the thing looks like a single throw relay with a normally open contact, with the armature being operated by heat rather than a magnetic coil.When the flasher unit heats up and switches, the contactor shorts the input terminal to output terminal, which kills the voltage that was driving the heater.Then the bimetal strip cools off, and the contact snaps back open, and the cycle starts over again.Current will not flow to operate the heater element without the proper load connected to the output terminal.To further understand how the whole flasher system works electrically, you need Ohms law and a simple power equation, like this_E=IR(voltage = current times resistance)P=(I^2)xR(Power = current squared times resistance)By algebraically manipulating these equations you can represent and solve the electrical conditions in the flasher system.When you put a voltmeter on the ‘unconnected’ output of the flasher unit you will see 12 volts, but only because it’s open circuit.If you touch it with a grounded test lamp, the lamp will light up, but not quite at full intensity.The resistance of the internal heater element is about 12 ohms.The resistance of a 3 watt test lamp is about 48 ohms.When connected in series this gives about 9.6 volts to drive the test light, which why it is not at full intensity, and you may read only about 2.4 volts at the flasher output terminal.Total circuit resistance is 60 ohms, so current flow is 0.2 amps.This generates about 0.5 watt of heat in the flasher, which is not sufficient to make it switch.When you connect two 21 watt turn signal bulbs in parallel, and connect those to the flasher unit, the external load resistance is only 3.4 ohms.In series with the heater in the flasher that makes 15.4 ohms total circuit resistance, which will allow current flow of 0.8 amp, which will generate 7.3 watts of heat in the heater element.At the same time each of the two light bulbs gets 0.4 amp and 1.1 watt of power at about 2.4 volts.This is insufficient to make the bulbs light up, but the bulbs are the necessary ground return path for the heater element in the flasher unit.This is the proper amount of current and heat to make the bimetal strip bend and switch over center.When the flasher switches like this it connects the flasher input terminal to the output terminal (and also to the pilot terminal).This applies the full 12 volts to the load to make the lamps light up.At the same time the heater element loses all drive voltage because both ends of the heater wire are then connected together by the switch (shorted).With no heat supplied, the bimetal strip then cools down until it relaxes and snaps back to the original rest position, opening the switch contact and killing the lamps.This also breaks the short across the heater element, and with power restored to the heater the cycle starts over and repeats, at about one flash per second.As a matter of some interest, it may be noted that there will be a short delay of about 1/2 second between the time power is first applied and when the turn signal lamps first light up. In the MGA 1500 car with the turn signal relay box, the first click you hear when the turn signal switch is activated will be the relay switching on, not the flasher unit.Although the flasher units have been known to last for decades, the eventual failure mode will most likely be a broken wire in the heater element.Before that happens it may develop a corroded contact for the pilot lamp, thereby disabling the indicator light on the dash while the turn signals still work.The next failure mode is very unlikely because the wiping contacts are generally self cleaning, but if the primary load contacts were badly corroded the flasher would switch to the actuated position and stay there as long as the power is on, as the contact would not be made to short our the heater power (and no power for the turn signal lamps).If you add a third 21 watt bulb (in parallel) to the load there will be about 1.1 ohm less total resistance in circuit (7% less resistance), the flasher will see a bit more working current (8% more current), the heater element will heat up faster (about 16% more heat), it will attain slightly higher temperature and will take longer to cool down (nearly double the time) before it switches back.This makes for an overall slower flasher rate with quite a bit more ‘on’ time and just a tiny bit less ‘off’ time.Total cycle time is then about 50% longer, or about 1.5 seconds per cycle.That’s not bad, because it tells me my trailer turn signal lamp is working when it flashes slower.But if one of the car’s two turn signal lamps is burned out or not properly connected, then the flasher unit sees double the external resistance (only one lamp connected), and it probably won’t flash at all (about 33% less heat in the flasher heater element).When it doesn’t switch, the turn signal lamps will never light up, because the rest position of the flasher is open circuit.Not flashing is the indication that there’s something wrong with your wiring, or that you have a burned out bulb, and no operating turn signal on that side of the car.Additionally, the MGA 1500 circuitry has the turn signals sharing the rear bulbs with the brake lights.That peculiarity (and associated quirks and problems)is discussed in the next lesson on the 1500 turn signal relay operation and fault diagnosis.
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Testing and replacing a flasher unit

There are two fundamental types of flasher units: continuous and intermittent. Unlike the other, one is controlled by a piece of wire or a bimetallic strip that expands and contracts as it is heated by the current, while the other is controlled by a transistorisedcircuit that operates as a relay. Because of the clicking sound it generates, it is easy to determine whether or not the first kind is functioning properly. Circuit testers or test lamps can be used in the manner indicated below to determine whether it is defective.

A short circuit has the potential to cause damage. A transistorised type can only be determined to be defective after all other components in the circuit have been eliminated from consideration.

Changing the flasher unit

When changing this sort of unit, be sure to label the leads so that they don’t get mixed up. An optional tiny bracket with one or two self-tapping screws, a pushfit in a spring clip, or a plug into the fusebox can be used to secure the flasher unit in position. Alternatively, it may just dangle from its wires below the instrument panel. With the exception of the plug-in kind, there is a possibility of the wires being confused. Before removing them, make sure they are properly labeled. The light on the instrument panel, which is linked to the switchchinstead, is not connected to a terminal on a two-terminal unit.

The type number is often stamped on the metal lid of the device.

Tracing faults

If the indicators cease to function entirely, first check the fuse or circuit breaker (SeeChecking and replacing fuses). The failure of other components in the same circuit as the blown fuse is a sign of a blown fuse. The components in the circuit should be identified in your vehicle’s owner’s manual or service manual. Replace the fuse with a fresh one. If it blows up again, check for a short circuit elsewhere in the system. If the fuse is in good working order, check the stalk and hazard-warning switches, as well as the flasher unit.

The flasher unit may be near by, or behind or under the bonnet or hooked into the fuse box (See) (See).

Testing the flasher unit

In order to ensure that electricity is reaching the flasher unit, use a test bulb. After starting the engine, ground the tester and probe the feed wire connector: the bulb should illuminate. The typical kind of flasher unit may be tested by connecting a circuit tester between the unit’s terminal marked B and the earth terminal on the unit. Start the engine by turning on the ignition. The lamp should illuminate if the supply side of the device is operating properly. Look for a break in the wiring between the device and the fuse box if this does not occur.

The lighting should be turned on, and it may even flash.

Fast or slow flashing

A flasher is needed to flash between 60 and 120 times per minute – that is, once or twice per second – in order to comply with the legislation. It indicates that you have a traditional kind of unit if the flashing speed becomes particularly fast or slow – the speed of a transistorised type is consistent. The flashing of a three-terminal unit that is more rapid than typical shows one blown bulb, as well as one that has become corroded or removed from the bulb holder.

It is possible that a partial short circuit is causing the flashing to occur more slowly than usual. If you have a two-terminal device, slow flashing suggests you have a blown bulb; quick flashing shows you have an incomplete circuit.

Hazard warning lamps

All contemporary automobiles are equipped with hazard warning lamps, which are intended to be used only when the vehicle is stopped and poses a threat to other drivers. It is necessary to bypassthe regular switch when using the danger warning switch since it sends signals to all the indicator lamps at the same time through the flasher unit.

Heavy-duty flashers

To make a heavy-duty flasher, bend the fourth terminal backwards. If a car is going to be used to pull a caravan or other form of trailer, an electrical connection connector for the trailer’s lights, as well as a tow bar, must be installed. The present flasher unit is not powerful enough to service the additional lamps, and a heavy-duty unit (or an additional remote unit) will need to be installed to serve the additional lamps. Using the heavy-duty device when travelling without a trailer allows you to use the car’s conventional flashers without affecting the flashing speed or putting additional strain on the lights themselves.

Before connecting the heavy-duty flasher unit, it may be necessary to bend the terminal prong to a 90-degree angle and attach the warning-lamp terminal to it before plugging it in.

A remote flasher unit instead of a heavy-duty flasher unit can be supplied if the automobile flasher unit is positioned in an awkward location, such as inside the instrument panel, according to tow-bar centers.

It must be hooked into the current flasher system in order to function properly.

The switch on the steering column

Frequently, a hazard-warning switch might be removed for testing purposes. The connectors on most new automobiles with multi-function switches on the steering column are sophisticated, and patience is required to thoroughly inspect them before driving. It is possible that the switch has been bent, broken, or has dirty connections, which prevent it from functioning on one or both sides. Connect the tester to one of the switch’s output terminals and to the grounding terminal. Turn the switch to the appropriate side while the engine is running.

If this is not the case, the switch is malfunctioning.

How does a car signal flasher work?

When you depress the turn- signalstalk button, the thermalflasher establishes a connection with the turn- signalbulbs through the turn- signalswitch. When this happens, the circuit is complete, and current can begin to flow. Because the spring steel does not make contact with the contact at first, the resistor is the only item that pulls power. The flasher relay is supplied by the 12-volt direct current (DC) power supply of the vehicle. It is grounded (either positively or negatively) in order to be consistent with the rest of the car’s electrical system.

After then, the issue becomes, ‘How do you connect a turn signal flasher?’ Take a wire from the positive side of your battery and connect it to theflasherinput (or either prong if your battery is not polarized) to complete the circuit.

To make a turn indication bulb, connect a lead from each of the outer terminals to the bulb. In the same vein, how do you test a three-pin flasher relay? How to Check the Function of a Three-Prong Flasher Relay

  1. Determine the locations of the terminals
  2. Connect the test light lead between the ‘P’ terminal of the battery and the negative terminal of the battery. Connect the ‘B’ terminal of the battery to the positive terminal of the battery using the test wire, which should have equal-length stripped ends and one clip on both ends.

What is the proper way to repair a turn signal relay? In fact, it’s one of the most straightforward fixes you’ll ever perform.

  1. Find the location of your relay cluster. This information may be found in the owner’s handbook for your vehicle. Locate the turn signal relay on your vehicle. This information should also be included in your owner’s handbook. Remove the old turn signal flasher relay and replace it with the new one after you’ve been able to inspect your relays.

Picking the Right Turn Signal Flasher for LED Lights

Turn signals are an absolutely necessary part of every vehicle. These include a flasher, a turn signal switch, indicator lights on the dash, single or dual filament lamps at the vehicle’s body corners, and an emergency flasher switch, among other components. It will be explained in this article how signal flashers work and how to select the most appropriate one for a turn signal with LED lights. Rather than the switch, a basic turn signal circuit begins with the flasher. An electrical contact is located within the circuit assembly and is responsible for transferring current from the fuse panel to the flasher.

  1. When a smaller piece of spring steel is connected with a bigger piece of spring steel, a piece of resistance wire is wrapped around the smaller piece.
  2. Resistance wires conduct current, which causes the spring steel around which they are wrapped to heat up as the current passes through them.
  3. When the piece of steel has been straightened, it is forced into direct electrical contact with the signal bulbs, bypassing the resistance wire and delivering the current directly to the bulbs.
  4. This causes the electrical contact to be broken, and the bulb filaments to be turned off.
  5. When the turn signal is activated, the clicking noise is caused by the spring steel bouncing back and forth in its housing.
  6. In addition, the switch assembly is programmed to automatically cancel itself.
  7. Once connected, the center contact may be used to distribute current to the right and left signals, depending on how the switch is moved.
  8. As a result of the fact that all of the lights described above are in grounded fixtures, the circuit is complete.
  9. The lights turn on and off in response to the contacts on the flasher opening and closing.

The real switch is designed in such a way that it overrides the turn signal switch and distributes current to both sides of the vehicle at the same time. It makes advantage of the already-existing flasher.

Using Flashers with LED Lights

LEDs (light-emitting diodes) are becoming increasingly used in automobile lighting. They have a very long service life, are extremely vibration resistant, and need significantly less packing space as compared to other bulb-type assemblies on the market. The use of LEDs for various signal tasks in passenger vehicles is rapidly becoming more common, as the desire for technical and stylistic advancements grows more intense. LEDs are used in flashing beacon lights on vehicles such as maintenance trucks, which are powered by batteries.

  • Because of the energy-efficient nature of LEDs, the engine may be turned off while the lights continue to flash.
  • After passing through the bimetal strip, the current completes the circuit and activates the front and rear turn signals while simultaneously heating the bimetal strip, forcing it to bend and open the circuit, resulting in the lights flashing.
  • Many automobiles also feature turn signals in their side mirrors, which helps drivers avoid being blinded by their surroundings.
  • The LEDs are installed behind the mirror glass so that the driver sees only a faintly illuminated arrow from within the vehicle, but other drivers outside the vehicle see a brightly illuminated arrow as well.
  • However, not all of them are suitable for usage in LED applications.
  • Another type of flasher is an electrical flasher with a ground wire for LEDs, which is another category.
  • LEDs provide a number of benefits over other lighting options.
  • Many aftermarket manufacturers have begun developing LED direct-fit lamp assemblies and LED replacement bulbs that may be used in lieu of the standard 1157 bulbs as a result of these advantages.

Using a regular flasher device may be sufficient in the event that there is an incandescent bulb anywhere in the circuit trying to flash. The introduction of a no-load LED flasher can into the flasher system provides a solution to this problem.


This article provides an overview of turn signalflashers for LED lights and how they work. In order to obtain further information on comparable items, please refer to our other guides or visit the Thomas Supplier Discovery Platform, which may be used to find possible sources of supply as well as see detailed product specifications.

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More from AutomationElectronics

Kapa65/ When it comes to automotive systems, turn signals are one of the most straightforward to diagnose. Your signal flashers are either operational or inoperative. It’s similar to being pregnant in that there is no such thing as a ‘kind of’ situation. It is not difficult to troubleshoot your turn signals. The following are the symptoms of a malfunctioning turn signal: fast blinking, continuous illumination, or no illumination. The good news is that all of these indications point to one of two likely causes: a faulty turn signal relay or a burned-out turn signal bulb.

If your turn signal does not illuminate at all or does not flash, you will need to replace the turn signal relay.

Some cars feature separate flasher relays for the turn signals and the danger lights, which can save on battery power.

Hazard warning lights may be quite useful.

Replacing the Turn Signal Relay

In the event that you find that you need to replace your turn signal relay, you’re in luck since it’s a simple process! In fact, it’s one of the most straightforward fixes you’ll ever perform.

  1. Find the location of your relay cluster. This information may be found in the owner’s handbook for your vehicle. Locate the turn signal relay on your vehicle. This information should also be included in your owner’s handbook. It is possible to obtain a service handbook for your vehicle if it is not
  2. Remove the old turn signal flasher relay and replace it with the new one after you’ve been able to view your relays clearly. Don’t be concerned about installing it improperly
  3. It will only travel in one direction, which is the correct direction.

That’s all there is to it! Now you’re back to your old habits of blinking and being a responsible driver on the road.

Further Troubleshooting

It is necessary to perform some semi-serious electrical troubleshooting if you have changed your turn signal relay and checked to make sure all of your turn signal bulbs are functioning properly but still have no functional turn signals after performing these procedures. Prepare yourself for a difficult experience because this is going to happen. Tracking out a stray wire or a ground that isn’t grounded may be a real pain in the back of the throat. But let’s get down to business.

Check the Connections

It was necessary to reach the back of the turn signal housings in order to replace the bulbs. You’ll also locate the plugs that link your tail lights and front turn signals to the vehicle’s electrical system in this area. Unplug each of them and then plug them back in one at a time. Occasionally, simply disconnecting and replugging the device will be sufficient to restore the connection and resolve your problem. You shouldn’t be shocked if one of the plugs that you didn’t believe had anything to do with the turn signal system turns out to be the source of your problem!

Look for Bad Grounds

If your turn signal does not light up at all or does not flash, it is possible that a poor ground connection is the cause of the malfunction. The ground wires in most automobiles will be either brown or black in color. If you suspect a ground wire, you’ll want to trace it from the bulb housing to its termination point, which is the point at which it screws or bolts into the vehicle’s chassis.

When you locate this, loosen and tighten the ground connection until it is secure. It’s even possible to remove it and clean everything with steel wool if you want to be really certain.

Check Random Fuses

This step may seem unnecessary, but because turn signal systems may be complicated, and I’ve seen a variety of inexplicable repairs for them, it’s a good idea to check all fuses if you’re changing a turn signal or dealing with other unexplained electrical problems. A defective circuit that appears to have nothing to do with the turn signals or brake lights might, in fact, be the cause of their failure in some cases.

Light Show—Picking The Right Turn Signal Flasher For LEDs

Q I just upgraded the parking lights and turn signals, as well as the taillights and turn signals, in my 1956 Chevrolet from incandescent to LED. The good news is that they are quite bright; the bad news is that the turn signals are no longer functional. I was aware that the turn signal flasher would need to be replaced, which I promptly did. I bought an electronic flasher from a local parts store, but it didn’t function out of the box. My next attempt was with a different sort of flasher that did not have a ground wire; this did not work either.

I’m sure there’s a method to make them function, I simply don’t know what it is at this moment.

In addition to completing the circuit and turning on the front and rear turn signals, the current passing through the bimetal strip warms the strip, causing it to bend and open the circuit, so turning off the lights and turning them back on.

When using LEDs, most mechanical flashers will not operate since they need a little amount of current flow, which is insufficient to heat the internal strip and open the circuit.

Some are just electrical rather than mechanical in nature, and are frequently used in applications such as vehicles with several flashing lights, for example.

A common problem with these devices is that they do not function correctly due to a bad ground connection.

Here is what he had to say about it: LED lights and flashers are becoming increasingly popular.

There are a number of advantages to using these kind of bulbs.

With this in mind, a number of aftermarket manufacturers have begun developing LED direct-fit lamp assemblies and LED replacement bulbs that may be used in place of the standard 1157 lamps.

On rare cases, a conventional flasher device will operate if there is an incandescent bulb anywhere in the circuit that you are attempting to flash.

In many earlier cars with original, OEM reproduction, or aftermarket dash harnesses, there was no need to index the flasher can connection, as was the case in many modern vehicles.

A fuse panel or power source is used to power the ‘X’ terminal on the flasher can, and the ‘L’ terminal on the flasher can is used to ‘load-out’ to the switch or lamp assembly.

The feed and output wires must be switched at the connection before installing the new LED flasher can if your harness does not have them arranged the same way as in the diagram above.

An orange ‘power-in’ feed is connected to the hazard circuit, while a brown ‘load-out’ feed is connected to it. Colors from other manufacturers will differ.

Diagnose The Turn Signals Dont Work Or Dont Work Properly – Auto Repair Help

DIAGNOSE – THE TURN SIGNALS DON’T WORK OR DON’T WORK PROPERLYBy CarlO’Reilly SYMPTOM SUMMARYThe turn signals do not flash or they may flash in only one position or one side may remain on constantly with the switch in the off position.USUAL CAUSEThe turn signals use a flasher unit that acts as a repetitive circuit breaker.This unit makes then breaks the electrical circuit that turns on the turn signal bulbs.The cycle will continue as long as the directional switch is turned on.This unit relies on heat build up caused by electrical current flow to determine when to break the circuit.When the switch is initially turned on, electrical current flows through the flasher unit to the bulbs.When this occurs, heat builds up in the flasher unit.When the heat reaches a predetermined temperature, a metal strip within the unit stretches due to the heat and breaks the electrical circuit turning the bulbs off.With the bulbs disconnected from the circuit, the flasher unit cools off.Once it has cooled, the metal strip re-contracts and re-closes the electrical circuit turning the bulbs back on.The usual cause of inoperative turn signals is a defective bulb or flasher unit.

CORRECTIVE ACTIONPrior to performing extensive diagnosis, check the vehicles fuses to ensure they are not blown.Some vehicles utilize two fuse boxes, one in the passenger compartment and another under the hood.Consult your owner’s manual for fuse box locations and fuse ratings.If the directionals only flash in one position and are off constantly in the other direction, the usual cause is a burnt-out bulb.When a bulb blows, the current flow in that side of the circuit will be reduced.The reduction in current flow prevents the flasher unit from reaching the needed temperature to switch the bulbs off.Turn the directionals in the position where they are inoperative and perform a visual inspection of the exterior bulbs.Replace any bulbs that are not lit.The flasher unit is used to switch the current on and off for both right and left directionals.If the turn signals are inoperative in both directions, a defective flasher unit or blown fuse is the usual cause.On most vehicles the flasher unit is located on the front or on the back side of the fuse box located in the passenger compartment.Some vehicles use a solid state flasher module that contains transistors and diodes.On these vehicles, you should consult a vehicle specific service manual for proper diagnosis.

PRECAUTIONS, TIPS and NOTES You should always use a replacement bulb of the same part number as the one being replaced.Your owner’s manual will indicate the correct bulbs for each location on the vehicle.Using the incorrect bulb can create too slow or rapid turn signal operation.Manufacturers often use grease to repel water from the bulb sockets.Do not remove this grease from the bulb socket when replacing defective bulbs.Continued onPart 2

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