• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

AC Sometimes Does Not Work While Stopped



It's happened about 5 times now. My AC just blows hot air when stopped but once I start moving, it gets cooler and blows as normal.

It seems to happen when it is very hot and humid.

I went on a 6 hour drive with no problems. It seems to be very intermittant but has happed about 5 times.

Any ideas?
As per a previous chief post have them check the Freon level...maybe it is low and at slow engine speed the low freon low pressure switch cuts out the compressor....

Good Luck
Hey Peter. My Avalanche was about a pound low on R-134 out of the box. My dealer flushed the system and recharged at no charge and my AC no longer behaves this way. My born on is 10/01 (don't know if that is a factor). I'm willing to guess if mine got out the door low others did too...

I had the exact problem you are describing...
I would definitely get it checked. It's been hotter than fire here, especially with the humidity. I ususally start the truck and then turn the temp all the way to the left so the fan is on full blast. The truck down pretty quick this way and that is with the truck standing still.

I always like to cool the truck down before I put the baby in the back seat. :B:
I have the same problem right now. Blows cold when go fast. i took it to the dealer the 1st time and they said the compressor was leaking so they changed the whole thing, and now its starting again. Im takin it tomorrow!
I am having many probs with my AV here are some

a/c dosnt work
All CD's skip
Front Bumper Misaligned
U-Joints Changed
Engine Knocking on a cold start
Sunroof Leaks
Back Windows Rattles
Emergenc brake dosnt hold good
Makes a knock when put in reverse
All Brakes bite and heat up

Lol there more but i forgot some
Ill keep ya updated

2002 Z71, Indiglo Blue, Loaded, Blue Lights on the whole front end, 18" SM Wrapped In Toyo's, Trenzo Billet Grill, Future Mods ( Sound System If i can find some space) Strobes, and paint the cladding.
I have the exact problem - to clarify only when the auto temp control is on - if I do not run in auto not a problem. So maybe I will go to the dealer to check freon level !!!???

Same problem, they replaced the cycling switch but didn't help. Between the abs and brake light coming on the A/C problem, the driveline noise... I love the truck, but..........
zzo2 said:
I have the exact problem - to clarify only when the auto temp control is on - if I do not run in auto not a problem. ?So maybe I will go to the dealer to check freon level !!!???


I seemed to have more problems in auto also - I'd have them check the freon...
My A/C was low on freon (or whatever it is now) out of the chute though sometimes I still have a problem when it's hot and very humid outside.
I had the same symptoms, and heres what helped mine.? When the vehicle has not been driven for several hours, Open the hood, shut the climate control off, and start the engine.? Walk up and feel how much airflow is coming from the engine fan.? It should be ALOT!? The fan clutch should not be slipping at all. If you rev it to about 1500 RPMs it should roar and keep roaring for quite a while.? If it isnt doing this, replace it.? Mine has 45K miles and was completely toast.? If your not sure if its moving enough air, go turn the AC on and set it to a medium fan speed.? Now go out there and grab ahold of the AC line coming from the condenser leading to the fixed orfice tube.? Depending on how hot it is outside you should be able to feel warmth, but not so hot you cant keep your hand on it.? If its really hot, replace the fan clutch.? When running the AC, if you dont hear that fan roar for about 30 seconds after stopping at traffic lights, you should replace it.? The more air it moves, the more comfortable your going to be.

Word to the wise, some cheap fan clutches will not begin to slip as soon as they should, costing you more money in gas.? The Dealer wanted $160 , But GMpartsDirect was about half that.? I bought a Hayden Clutch from Orilleys for $60 and it works beautifully.? I am very happy

Anyone else getting 45 degree air blowing out of their vents? :0: