I am having some issues with the AC on my 2500HD and hoped someone else on here knew of some things I could do to fix it.

What it does...

When parked or at a stop light the AC will start to blow hot air. The air previously was cold and then when sitting for a min or two at a light it will start to blow hot air. It doesn't do it all the time but enough to make me concerned for the AC system. Last weekend I had the truck parked and turned on the AC, the truck had been sitting for the day. It was about 80 degrees outside. The HVAC was only blowing hot air and would not get cold. I could hear something under the dash turn on and then off, it sounded almost like the release of air or cycling of some sort. I decided to drive the pickup to see if driving would help the problem. I got about a mile and 1/2 and the AC started blowing cold air again and it stayed cold. I didn't keep driving the truck to see if it would cycle back to hot air.

What I've tried...

I hooked up a freon refill bottle to the system last summer to recharge it. If I remember right it didn't take much of the freon.
The compressor sounds good, as far as I can tell.

Any insight would be appreciated.

Thanks

 

Check the blower motor resistor

http://www.justanswer.com/chevy/701x...e-checked.html

 

It gets hotter while sittin due to the motor gettin hotter or somethin like that. Let me guess, when you take off after sittin for a few minutes and the AC runnin, you sound like a jet plane don't ya? Replace the clutch fan with electrics fans and the AC won't get "hot" sittin in traffic

 

Country is right on the money. Too much heat build up in the coils behind radiator. 10 yr ac guy.. Also make sure the extra heatts not due to bad water pump or even old tranny fluid.