alright im new to this forum stuff but im going out of my mind! i have a 00 jetta glx vr6 & it seems everytime i drive the car for about 5 minutes or more with the ac on, the temp on the dash drops all of a sudden. it may read 88 & suddenly it goes down into the negatives. once that happens the ac blows nothin but hot air. Any ideas what it could be? Really need help please! thanx!