Have a 99 Ram 2500, approx 45K, just replaced A/C clutch, compressor and drier. Problem is when de-accelerating A/C not blowing cold air, hot air coming from vents, no vent changes, the when idle returns cool air comes back out of the vents.
What could it be?
Tucson is still hot this time of year!!! Need help soon!!!!
Sponge Bob

 

If I'm not mistaken (which I probably am) all of that stuff is vacuum operated. Sounds like something got hooked back up incorrectly.

 

I have a '99 5.9L 1500 4X4 with a similar issue. Although I only seem to notice it when I come to my first stop after starting the truck. Additionally I notice other times it if I really have to get on the brakes. Have you had any success in isolating this problem?