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2002 Envoy stops running when I turn on a/c and the defrost won't blow at the top of dashboard but when heat turned on it does fine

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For whacky temperatures and discharge locations, disconnect the + cable from the battery for a minute. Then reconnect it solidly. This will cause the mixer doors to recalibrate and work as expected once again.

My 04 Envoy's engine RPM would drop when idling in gear at a traffic light, etc. with the A/C on - and the air wouldn't be as cold. It didn't stall though. Have you changed your spark plugs yet? Should be done at 100k/mi. It may be time for a tune up, too.

Posted on Apr 22, 2014

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Posted on Jan 02, 2017

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SOURCE: Heater/AC only works thru defroster vents on '98 Contour

you prob have a vac leak on the back of the intake. good luck

Posted on Nov 23, 2008

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I'd concentrate on IAC (idle air control,)motor, or AIS (automatic idle speed) motor. I believe on your vehicle, it's probably referred to as IAC motor, but either way, same thing, they control your idle during load conditions such as your experiencing. Have had good luck just removing it & cleaning the pintle on it & port (hole) that it comes out of with throttle body cleaner spray. If it cures it for a while, then starts to act up again, replace it. Should be mounted at front/side area of throttle body. be careful not to damage, or lose, "O'" ring at the base of where it mounts to throttle body. If you look the part up online at autozone, or pep boys, you'll know what to look for if not familiar with it.

Posted on Mar 12, 2009

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SOURCE: I have a 2002 GMC Envoy and it turns off when I turn the AC on?

could be the a/c compressor ...

Posted on Jul 20, 2009

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SOURCE: 1999 Volvo S70 heater and defroster blowing "fog"

suspect leaking heater core.check coolant level.

Posted on Sep 29, 2009

  • 714 Answers

SOURCE: 2002 Ford Explorer When turned to defrost air

sounds like your door blend actuator which is under the dash and a pain to replace

Posted on Feb 17, 2010

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I have a knocking noise coming from the dashboard area of my 2002 Infiniti i30 when I turn the heat on defrost it stops

Inside the box where all your component inside the ac box r little doors that open to give you defrost n heat there like 4 small door you need to see if one of those door not is stuck inside a peace of napkin or paper that will make it do that noise get back good luck

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Why my A/C condenser fan won t stop running, dodge ram 2008

To clarify, the compressor and fan will run in defrost mode. The compressor and fan runs to dry out the air blowing onto the windshield.
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2002 GMC Envoy shuts off when air or heat turned on

The automatic idle control module is bad.

May 02, 2014 | 2002 GMC Envoy

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What causes my 2002 Envoy to stop running when I turn on a/c? Also defrost won't work ion dash vents

could be a low charge rate from alternater as a/c uses masses of power so could be enough to stop other electrical units operating

Apr 22, 2014 | Cars & Trucks

1 Answer

My envoy idles up and down when i turn my defroster is on

When you place your controls on defrost it turns your air conditioner on - depending what the heat level is set on the air conditioner will cycle on and off to regulate temp. Anytime the A/C runs the idle sensor will bring the idle up

Mar 25, 2013 | 2003 GMC Envoy

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I have a 2002 GMC Envoy XL that blows cold air from the rear heat vents. What could the cause be?

the heat accuator could be bad. It is a motorized part that adjusts your temprature by allowing cold or warm air flow when you adjust the temprature at the knob you are turning

Jan 21, 2011 | 2002 GMC Envoy

1 Answer

Heat and defrost will not turn on motor sound to it

Check the fuse for the blower motor, and if fuse checks out fine, then have your blower motor replaced. I believe it is located behind the dashboard.

Good Luck

Oct 19, 2010 | 2002 Mitsubishi Galant

1 Answer

The fan that blows both AC and heat has quit working on my 2002 Envoy. At first, it took several minutes to begin blowing after being turned on, now nothing. Any ideas?

check the heater eliment under the passenger side of the truck ,remove the black cover and wiggle the plug they tend to loose connection

Nov 09, 2009 | 2002 GMC Envoy

1 Answer

02 envoy - "A/C on" indicator (front defrost) causes power loss.

the a/c will always turn on with defrost so the hot air wont crack a cold sounds like altenator not keeping up. have it tested.if the engine realy boogs down with the a/c turned on the a/c compressor might be bad.(locking up)

Dec 29, 2008 | 2002 GMC Envoy

1 Answer

Why does my heater keep running after I shut my Envoy off?

I have the same problem. I have also been searching the web for a solution. I came across someone saying that it was the heater module located behind the glove department. I can't find now where i read this but it said the part was approx. $150.00. He was having same problem as us, heater wouldn't obey touch commands to turn on/off or when heater did blow it would only blow real low or real high. Like you, after turning off engine blower motor was still running even though it wasn't blowing air out.
I'm tired of paying for things that are not due to normal "wear and tear" on my 2003 Envoy. Let me know if this helps you and how you repaired it. I'll probably have to take mine to the shop but because I'm a "girl" I swear they think I'm crazy with all my Envoy complaints.

Dec 01, 2008 | 2003 GMC Envoy

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