blue -

I can't give you technical help, but I know I saw a thread that will lead you to some good answers and understanding of the a/c system and the various sensors etc. that affect its operation. I think STEVEBFL even did a comprehensive write up about our systems that is linked in a thread. Do a search...

That being said, I wouldn't go back to that dealer with the problem if that is as far as they got the first time (its reasonably simple for somebody with the training and diagnostic tools to track down the source of the problem). Maybe they don't want to work on it?

The monovalve controls coolant flow to the heater core. Its on the firewall, almost dead center in front of the passenger. Look for a little assy. with a square black plate on top with a stainless cylinder (about the size of a dime) popping up through it. Its a five minute job to pop the little valve out and check the rubbers; $20+/- part to replace if the rubbers are shot.

Kevin