I have strange problem with air conditioning on my 95, 5.2. It blows cold air well, but when accelerating, the cold air shifts from the chest area to the leg area. As soon as the acceleration load is off, the cool air blows out the top again.

The vacuum reservoir holds vacuum well and check valve is working. I clamped off the cruise control vacuum line, but that had no effect. If I apply vacuum to the climate control vacuum line, it doesn’t hold vacuum. I’m not sure whether it should hold vacuum or not. I guess I could pull out the HVAC control box and check the vacuum lines there. Anyone else ever have this problem.

 

Need a second check valve, and/or a larger reservoir. You are experiencing what is called "wild vents", I think there is a thread about it in the DIY/FAQ section.

 

Thanks Hey. I read a few of the wild vent posts. I’ll try check valves and a second reservoir.

 

Inadequate manifold vacuum results in a flapper door actuator that won't hold position. There could be a fault in the existing vacuum line that's allowing too much to leak away or you have no reservoir...I don't remember if Dak has a vac reservoir or not but you could add one if you found no other leaks in the system.

Steve