I just purchased a 325CI Conv (2002) for my 16 year old daughter, car is in great shape, 105k, everything works great, however, every once in awhile, the AC is on, and it blows hot air through the center vents, and the dials are in the blue. it does not happen, on a regular time table, just maybe once a week, you can cut the car off for a bit, and it works fine and will for days on in...but when it does happen, it will stay that way, until, you turn the car off for a period of time. the AC is charged, clutch gap is great and working fine. is it something with the temp sending unit outside or what?????