just had mine serviced today
Took mine in for A/C service today for no cold air at all. The service tech and I worked on it side by side and follwed all the proceedures from GM. We checked the pcm, it's ok, we checked the module under the dashhbehind the glove box, it's ok, we checked the signal to the module in the roof stowage area, it's ok. we decided to unplug all a/c control wires on each module and check terrminals, they all seemed fine. Plugged everything back in and Voila, cold air again. Go figure, we hadn't replaced any parts just checked the connections.
We figured at this point we would let it sit while we attempted to get into the center console that the wife couldn't get into. After disassembling as much of the consloe as we could to get to the latch mechanism, we found that the lock system was broken inside, and wouldn't release the console tab. Went to the parts man and found that he had to order the entire center piece. I told him if that's what we have to do to get the one piece we need, then let's get it and we can change out just the lock when it comes in. Certainly don't want ot paint the upper section of the center console again.
Tried the air again before I left, and it is working better than it has before. If this occurs again we're going to order a control module (the on in the stowage area).