I have an 07 Tahoe that has given me some fits lately. It stopped blowing hot air. Got it looked at, no leak detected, recharged freon as it was almost gone. 3 weeks later same thing! Changed some tubing after detecting leak, recharged freon again--worked great until 3 weeks later no cold air! Tubing covered with foam stuff and no leak detected. Purple dye added to freon and was not detected leaking anywhere they saw. Said it had to be 1 of 2 places they hadn't looked yet. Either a part behind the dash or in the back of the car--both required car being taken apart. Started with the back and it tested fine. Pulled out dash and tested this part and apparently (per them) was the issue ($1500 later!) now 3 weeks later I may be crazy but it doesn't feel as if the air is as cold as before and the rear ac makes a hissing/air compression noise very frequently. What is the deal?!?! :help:
