Originally Posted by Chevrolet Customer Svc
Hopefully that gets things sorted out for you Camaromann. I did get your message and I'm sorry to see that you're still having issues.
Jeff Morris, Chevrolet Customer Service
To repeat my problem: The A/C was inconsistent and going from cold to warm to cold - on a repeated cycle. No strange smells, no clicking noises, and the compressor did not appear to be cycling on and off.
Okay....after five hours at the local dealer, the A/C is finally working like it should. (SO FAR)
First, the mechanic removed all of the 134a from the system and checked the content. He found that there was 2 ounces of freon TOO MUCH. The system is supposed to have .54kg (approx. 19 ounces) and my car had .61kg (approx. 21 ounces).
Then, he called GM to check if there was anything in their database relating to A/C issues for 2012, and asked them if having 2 extra ounces of 134a would effect the system's performance. Nothing to report from GM.
Then he refilled the system with the proper amount of 134a, and then hooked up a laptop computer to recalibrate the actuators for the internal dampening doors. Finally, he checked the A/C system control board.
We went drove for a 3 mile test drive in 95 degree weather, and the A/C was (finally) ice cold. More importantly, it stayed cold
and did not cycle cold/warm/cold like before.
The mechanic thinks that the extra freon might have caused higher operating pressure, which might cuase the compressor to cycle too frequently. But, only 2 extra ounces - he discounted that as a reason for the problem. He did conclude that the recalibrating of the actuators for the dampening doors is most likely the reason for my issues. He explained that these doors open and close (to blend the cold air with heated air to acheive the desired temperature) based on an electrical voltage variations. He explained that the compressor is always working like it should, but that it is most likely that I was getting warm air blending intermittantly with cold air.
Problem solved. SO FAR. I have driven my car another 35 miles during intense afternoon heat & humidity, and all appears to work well.