I've got a 92 model, 740T wagon with ac problems. To get to the skinny, bought the car charged the system, worked for a couple of weeks, no ac light in dash, mechanic (who's fairly knowledgable with Volvo's) says ac relay in the controls is fried. Replaced climate control unit with a known good unit, worked for a couple of weeks, then no light, compressor won't engage, same problem as before. The compressor itsself didn't sound real healthy, squealed intermittently and bogged the car down noticeably when engaged.

My question is, is the compressor most likely faulty and causing the ac relay (climate control to fail), if that's the case I will replace it along with the drier whatever else needs to be changed. Next question can the climate control units be repaired and if so who can do this. I haven't priced a new unit from the dealer (most likely expensive, if available) and I feel like if buying one from the junk yard i'm taking a chance on getting a bad one. Sorry to be so long, any advice appreciated. Thanks