Climate Controls / Air Flow Selections Problem

[frankmako]

I got a problem with my Air Flow selection of the climate controls in my 2004. No matter which selection I have the setting on the air flow goes through the windshield defroster vents. It only works right about 10 % of the time.


Also, in my 1995 F350 the air flow changes selection on it on. It goes from vent, to defroster vents, to floor vents, and back again no matter what the knob is set to.

What do I need to look for and/or change out to correct this problem.

[USAFBowman]

I had the exact same problem on my 2004. It is a problem with the vacuum pump on the passenger side of the engine bay, this pump is also used for your automatic four wheel drive. Being made of plastic it is known to crack. That should fix your climate control problem.

The way to know if that is your problem or not you will hear it pumping all the time, unlike if it works where it will only pump for a short time.