Air only blows through defrost vents?

Check the vacuum lines to the engine and see if any of them are broken, has a hole, or is disconnected. Check the vacuum hose on the blend door and see if it has came off or broke. For the rear defroster, check the switch to the defroster and make sure that it has power to it and power coming out.

thedieselstop.com

  • No matter what setting it’s on, or speed, it all comes out the defrost vents. So if I turn the AC on it will eventually blow cool air through the defroster vents while I’m driving, if I come to a stand still the AC air coming through the defroster vents will not be as cool, more musty.

Why is my air not coming through the vents?

The most common cause of low air flow through the vents in your home is blocked or dirty AC filters. Be sure to keep the area around your AC filters clear of furniture and anything else that might block the flow of air, and be sure to clean or change your AC filters once a month.

Does your blower motor control the defrost?

Bad Blower: The heating and defrosting system rely on an electric blower motor to move the hot air into the cabin of the car and through the defroster vents. If the blower motor is malfunctioning, the defroster will not work. Issues can range from a blown fuse to a bad blower speed controller.

Why is my defrost not blowing air from vents?

Front Windshield Defroster Fixes When a front defroster stops working, it’s usually a faulty switch or blend door if air comes out of the other vents or a bad blower motor if no air comes out of the vents. Keep in mind that if the heat isn’t working, that doesn’t mean that the front defroster is also broken.

How much air should blowing out of the vents?

The air coming out of your vents should be roughly equal throughout your whole house. A bathroom fan, for example, should be able to pump a minimum of 50 cubic feet of air per minute.

How do you unclog air ducts?

Step-by-Step duct cleaning

  1. Remove the screws from air duct covers and return-air grill plates.
  2. Cover up your supply vents (those vents that supply heat or air to the rooms) with paper towels.
  3. Set your thermostat to the “fan on” position.
  4. Loosen dust in ducts.
  5. Clean supply registers.
  6. Clean the return registers.

How do you tell if coils are frozen?

Signs of a Frozen Evaporator Coil

  1. Your AC is not cooling.
  2. Ice is present around the outdoor refrigerant line.
  3. Your evaporator coil has condensation and/or ice forming on it.
  4. The condensate drain line is clogged.
  5. The condensate drain pan is overflowing.

What are the symptoms of a bad blower motor?

What Are Signs Your Blower Motor Needs to Be Replaced?

  • Poor or Airflow from Air Vents. This will be the first and most obvious sign your blower motor has a problem.
  • No Airflow At All From Vents.
  • Skyrocketing Energy Bills.
  • Strange Noises When You Turn on the Heat.
  • Overheating Blower / Weird Smells.

How much does it cost to replace a blower motor?

Replacing a blower motor costs $450 on average with a typical range of $250 to $800. With a warranty, you might pay as little as $150 for labor alone. For high-end models, like those with large motors or access issues, you might pay as much as $2,000.

Where do defrost vents lead to?

the defroster vent is a tube that runs into the heater tube and down to the heater vent / core.

How much does it cost to fix a blend door actuator?

Blend Door Actuator Replacement Cost The blend door actuator usually costs between $100 – $300 depending on the car’s make and model, before labor costs. On average you can expect to pay around $150 for the actuator itself.

What are the symptoms of a bad blend door actuator?

Signs You Need A New Blend Door Actuator

  • Knocking. Knocking sounds can almost always be attributed to a failing blend door actuator.
  • Clicking.
  • Any Other Strange Noises.
  • Inconsistent Airflow.
  • Inconsistent Temperature.
  • Wrong Temperature.

Why wont my vents work in my car?

Here are some of the most common causes of why air doesn’t flow out of your vehicle’s vents: Your air intake is clogged, meaning that air isn’t getting in from the outside at all or isn’t circulating properly. There is a blown fuse in the ventilation system. Electrical issues such as a bad relay.

How do I get more air flow out of my vents?

5 Ways to Improve Airflow in Your Home

  1. Check Vents and Registers. One of the simplest things you can do to increase airflow in your home is to check the vents and registers in each room.
  2. Turn on Ceiling Fans.
  3. Schedule HVAC Maintenance.
  4. Consider Duct Cleaning.
  5. Invest in a Ventilator.

Does duct cleaning help air flow?

Ductwork cleaning does not improve air flow (and can actually help impede it), does not permanently remove mold or odors, and, depending on the type of ductwork, actually cause damage. Consult a certified HVAC specialist to determine the best solution to maintain your ductwork.

See also:  Acura engine knocking noise?

What do I do if my AC isnt blowing cold air?

Try cleaning your air conditioner’s filter and the coils to see if improving the airflow fixes the problem. If there is ice buildup, you’ll need to run the unit with just the fan in order to melt it off. If that doesn’t get the unit blowing cold air again, it could be refrigerant levels are low (see below).

AC blows through defrost vents when accelerating

11-04-2016, 05:27 AM 1
Platinum MemberJoin Date: Nov 2016Location: COLORADOPosts: 151 AC blows through defrost vents when accelerating


Anyone ever have this problem?The AC blows through the dash vents just fine when crusing, but if I accelerate to pass someone or going up a hill, it starts blowing air through the defrost vents only.Anyone else have this issue?If so, is the fix DIY?Thanks,Mark_

11-04-2016, 05:34 AM 2
Platinum MemberJoin Date: Sep 2015Location: New YorkPosts: 133

Quote:Originally Posted bysaenzmAnyone ever have this problem?The AC blows through the dash vents just fine when crusing, but if I accelerate to pass someone or going up a hill, it starts blowing air through the defrost vents only.Anyone else have this issue?If so, is the fix DIY?Thanks,MarkYou have a leak in the air vacuum system that controls the air flappers. When you step on the gas you loose engine vacuum and with the leak the flapper vacuum goes down also._

11-04-2016, 06:12 AM 3
Platinum MemberJoin Date: Nov 2016Location: COLORADOPosts: 151

Quote:Originally Posted byDCHittYou have a leak in the air vacuum system that controls the air flappers. When you step on the gas you loose engine vacuum and with the leak the flapper vacuum goes down also.Is this a DIY fix or better left to the pros?Thanks,Mark

11-04-2016, 01:17 PM 4
Platinum MemberJoin Date: May 2016Location: EastPosts: 2,484

Quote:Originally Posted bysaenzmIs this a DIY fix or better left to the pros?Thanks,MarkIt is not too difficult. no special tools needed. But it does take time. Disassembly required.Check the youtube for video.ps. I have posted the links here before, but I have forgotten which thread.

11-07-2016, 01:26 AM 5
Platinum MemberJoin Date: Sep 2016Location: Southern AB, CANPosts: 183

I’m guessing that there is a default in the program that controls the HVAC.Defrosting the windows being more important than cooling the occupants the program may go to that setting under loading of the engine. A/C compressor ‘usually’ kicks in to dry the cab air when in defrost mode.Just guessing on this one though.

11-07-2016, 02:08 AM 6
Platinum MemberJoin Date: Sep 2015Location: New YorkPosts: 133

Quote:Originally Posted byMarleyI’m guessing that there is a default in the program that controls the HVAC.The flappers are usually just spring loaded so when the vacuum is lost the spring wins. I guess that does make it go to a default but I doubt it is in a program.

11-07-2016, 02:47 AM 7
Platinum MemberJoin Date: Jul 2014Location: ManitobaPosts: 677

Vacuum drops under wide open throttle (WOT). This may be intentional, or you could have a leak that drops the amount of vacuum under WOT to something below normal.First thing to do is start the vehicle with the hood open and listen for any noise like a sucking/hissing noise. The vacuum hoses are small and you may not be able to see them within the mess of stuff under the hood.You didn’t state what year of vehicle. But you may also be able to see a vacuum leak code if you connect a scan tool.

11-07-2016, 02:52 AM 8
Platinum MemberJoin Date: Aug 2010Location: MinnesotaPosts: 10,260

A lot of vehicles will have a vacuum accumulator tank somewhere.It is a very good place to hook up a vacuum pump and see if it holds vacuum.It will also allow you to check for leaks without the engine running.If you think you find a leak, or a suspicious hose or connection, you can spray it with a tiny bit of ether and the engine will speed up a bit for an instant.If you are under the dash, you have to be very careful not to gas yourself or start a fire, though.

11-07-2016, 11:58 AM 9
Platinum MemberJoin Date: Aug 2014Location: Brampton,OntarioPosts: 244

I have the exact same problem on my 97 dodge roadtrek, I have replaced alot of the small vacum lines under the hood, but still hasnt fixed it, next I will start under the dash, I dont seeone of those vacum storage balls, im actually thinking of adding one if I cant find the problem,

11-07-2016, 09:32 PM 10
Platinum MemberJoin Date: Nov 2014Location: PHX, AZPosts: 1,997

having a yard full of old cars (and everything on Cadillacs was vacuum.)you can use a piece of hose as a stethoscope and listen for whistling near hosesbe ready to replace a bunch of hosegolf tees can be used to block off hoses while diagnosinga vacuum gauge is handyan emisions manual (such as mitchell) will have complete vacuum hose routing for the underhood systems- once those are known good you can check the auxillary systems- other wise you can have a pushme-pullyou effect from a bad EGR hose or something.be methodicalmike

11-14-2016, 02:46 PM 11
Platinum MemberJoin Date: Nov 2016Location: COLORADOPosts: 151

I looked under the hood for the vacuum leak and didn’t see anything wit the naked eye.I keep hearing about a ‘ball’a vacuum ball that controls the flapper?Does anyone know anything about this?Where I can find it specifically?Thanks,Mark

11-14-2016, 02:51 PM 12
Platinum MemberJoin Date: Aug 2010Location: MinnesotaPosts: 10,260

Quote:Originally Posted bysaenzmI looked under the hood for the vacuum leak and didn’t see anything wit the naked eye.I keep hearing about a ‘ball’a vacuum ball that controls the flapper?Does anyone know anything about this?Where I can find it specifically?Thanks,MarkNot all vehicles have a ball vacuum accumulator.They may have some other shape, or no accumulator at all.I have seen many of them mounted on the engine compartment fenderwells, some under the battery tray, some under the dash.It is best to find a vacuum hose map for both the engine and for the heater in a service manual, so you aren’t flying blind.Googling the make and model for one might show one up also.

11-15-2016, 03:03 AM 14
Platinum MemberJoin Date: Aug 2014Location: Brampton,OntarioPosts: 244

The accumulator ball on my 97 is located down behind the passenger side headlight, and I finally fixed my vaccum issues, turned out to be the 2 check valves, replaced them and it fixed all my problems, learned that fix from the dodge/mopar help site, very cheap and easy fix, hope this helps,_

Posting Rules
Youmay notpost new threadsYoumay notpost repliesYoumay notpost attachmentsYoumay notedit your posts


BB codeisOnSmiliesareOncode isOnHTML code isOffTrackbacksareOff PingbacksareOff RefbacksareOff


Forum Rules

A/C ,Heat, blows from defrost vents only (Solved)

Greetings to everyone. This is my first post, and I’m a new man. I was experiencing similar issue and decided to look into it online. Approximately 95% of those polled believed the actuator was faulty and needed to be replaced. Replacement of the actuator is a headache and will cost you around $50 to do. I saw the following on the internet and decided to give it a shot. It turned out to be successful. Occasionally, it appears that the actuators become stuck when the battery is unplugged and that they must undergo some sort of reset or recalibration.

  1. I had the same same problem, and this solved it for me.
  2. After I replaced my battery, I noticed that air was only blowing out of the defrost vents.
  3. 2) Turn on the vehicle.
  4. The distribution **** (for want of a better phrase) should be cycled if this is the case.
  5. It was necessary for me to do this before it would cycle.
  6. 5) The air conditioning then begins to blow via the dash vents.
  7. 7) Turn off the truck’s engine.
  8. This is what I did, and everything is working well now.
  9. Best of luck.

Dash air blowing through defrost vents only

This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
09-17-2018, 06:01 PM 1
Senior MemberJoin Date: Mar 2014Location: MIPosts: 108 Dash air blowing through defrost vents only


I have a new to me 2005 Winnebago Journey 32T. The dash a/c only blows air through the defrost vents only. Same thing in a/c, max a/c and even in heat setting. Is there a damper under the dash somewhere that could be stuck? A damper actuator that could be bad?_Nomad

Join the1 RV Forum Today – It’s Totally Free!iRV2.com RV Community -Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you’ll find that iRV2 is a great community to join. Best of all it’s totally FREE!You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners,see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!
09-17-2018, 06:32 PM 2
Senior MemberWinnebago Owners ClubJoin Date: Oct 2015Location: Edmond OKPosts: 161 Won’t swear on your Journey, but my experience on other vehicles is it is a vacuum hose/leak/check valve that is the cause.Good luck
09-17-2018, 06:42 PM 3
Senior MemberJoin Date: Jul 2014Posts: 29,360 The small vacuum hose from the intake manifold to the heater control is probably bad or disconnected.When there is no vacuum to the dash control, it defaults to defrost mode.Someone just posted about the same issue. He found the hose disconnected under the dash and discovered it went into the middle of a multi hose connector under the dash.
09-17-2018, 10:17 PM 4
Senior MemberJoin Date: Mar 2014Location: MIPosts: 108 Thanks JPO1980 and twinboat for your responses. I went through the parts PDF tonight and found there is a vacuum pump and 2 or 3 servo’s that operate dampers. I’m sure they are controlled by the heat and cool controller in the dash. I’ll check the vacuum pump first. If that’s working the dash will have to come apart_Nomad
09-17-2018, 10:27 PM 5
Senior MemberJoin Date: Apr 2011Location: Powell River, B.C.Posts: 24,936 The vacuum pump is on diesel chassis coaches, is your 32 footer diesel powered?Gas chassis use intake manifold vacuum.Defrost is the default setting, actuators are spring loaded to set the entire system to defrost once there is no vacuum._99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 30602000 Caravan toad, RemcoBlue Ox.
09-24-2018, 04:43 PM 6
Senior MemberWinnebago Owners ClubJoin Date: Oct 2008Posts: 418 Defrost is default position


On your dash is the rotary Heat/AC control. I had the exact same failure on mine. I had to replace the controller. Make sure you match replacement exactly to the one you have

09-25-2018, 08:15 PM 7
Senior MemberJoin Date: Mar 2014Location: MIPosts: 108 This problem has been fixed! In the Freightliner supplement that came with the motorhome I found a schematic of the vacuum operated dampers and control system. After familiarizing myself with the components I was able to locate under the small front hood the vacuum canister and vacuum pump. The rubber tubing was connected to the each of the components as they should be and then penetrated the firewall I assume to the dash controls. I then looked for the 12 volt terminals on the vacuum pump and determined only 1 wire was connected. I then found the 2nd wire and reconnected it to the spade terminal on the pump. Now the dash system actuators operate as they should and divert air to the appropriate diffusers depending on the control settings ie. heat, defrost, a/c, a/c max and vent. Thanks to everyone who contributed information and helped me fix this. I really appreciate your help._Nomad
Currently Active Users Viewing This Thread: 1(0 members and 1 guests)
Posting Rules
Youmay notpost new threadsYoumay notpost repliesYoumay notpost attachmentsYoumay notedit your posts


BB codeisOn SmiliesareOn code isOnHTML code isOffTrackbacksareOff PingbacksareOff RefbacksareOff


Forum Rules

Similar Threads
Thread Thread Starter Forum Replies Last Post
Air Conditioning blowing out defrost vents. twinboat Class C Motorhome Discussions 9 08-26-201810:57 PM
Dash AC only comes thru defrost vents Jimbabs Monaco Owner’s Forum 15 07-20-201202:03 PM
Dash A/C blowing out of defrost vents only cae2583 Class A Motorhome Discussions 3 07-19-201111:17 AM
ONLY dash air from defrost vents DadD45 MH-General DiscussionsProblems 9 05-20-200804:47 PM
dash air blowing out of defrost vents? softballdad25 Workhorse and Chevrolet Chassis Motorhome Forum 5 09-03-200708:40 PM

air wont blow out of vents . only defroster

The original post was made by kimmer415 However, since we are on the subject, my a/c compressor continues to cycle the compressor clutch approximately every 45 seconds because the relay near the unit on the firewall clicks. This appears to occur even when the device is set to solely provide fresh air. Do you have any suggestions? That is the AC Cycling Switch, and its purpose is to cycle the compressor on and off in order to avoid the evaporator coil from becoming iced over. When the threat of freezing is no longer present, the compressor is turned back on.

The frequency with which the system cycles is determined by a number of factors, including the temperature of the interior, the temperature of the surrounding environment, the engine RPM, and the amount of refrigerant in the system.

You don’t provide any hints as to what kind of vehicle you’re driving.

On a late-model Ranger, the compressor clutch should not activate when the mode selection is set to Off, Vent Only, or Floor Only (if the vehicle is equipped with one). The compressor clutch can be activated by the PCM control in any of the remaining five settings.

Air only blows through defrost vents

Only defrost air is blown through the vents; you are unable to modify the heating settings. Escalade, Avalanche, Silverado, Suburban, Tahoe, and Yukon are just a few of the models available. TSB,04-01-38-008 A technical service bulletin (TSB)04-01-38-008 has been published by General Motors to address issues with the heating system, blower control, and airflow for the following models: Cadillac Escalade, Escalade ESV, and Escalade EXT models from 2003 to 2005. Chevrolet Avalanche, Silverado, Suburban, and Tahoe models from 2003 to 2005.

If you scan your vehicle with a scan tool, you may also discover that the following fault codes have been stored: As well as B0229 Recirculation Actuator and B0414 Left and Right Air Temperature Actuators, there are also B3770 Mode Actuator and B0424 Right Air Temperature Actuator.

When the HVAC actuator harness made contact with a metal support brace under the instrument panel, it is possible that the brace cut through the wiring that controls or feeds back to the actuator control or feedback wires.

Then, on the left side of the aperture, you’ll want to find the actuator harness.

Apply friction tape over the sharp edge of the instrument panel bracing to protect it from damage.

Rick Muscoplat was born in the year 2012.

Leave a Comment

Your email address will not be published. Required fields are marked *