mine has the same problem and nobody can seem to figure it out, the compressor runs all the time then I guess it overheats and shuts down, but this only happends when its above 75 deg, below that it will cycle on and off. I shuts off sometimes whenever it feels like, im going on my 3rd mechanic and 600 bucks later my a/c still shutting down, took it to volvo and they wanted to replace evap coil and compressor for 2200 ouch!! they also told me its leaking freon, which its not because its been doing this for over a year now and ive had no freon loss. this seems to be a big problem with these cars and ive posted many messages about this problem on the brick and I must say nobody has a clue what im talking about and how to fix it. im very fustrated and really want to keep the car but dont want to put 2200 into it. if you come up with any solutions from anybody please email me @ compucat00@yahoo.com good luck and remember your problem will only get worse till its figured out. kelly