The air in our truck doesn't stay where you set it. It moves around from the floor to the defrost & so on... I had a 99 ram quite some time ago that did the exact same thing. I sold it before I ever go a chance to fix it but I think I remember someone telling me that it was a vac leak problem. Anyone else had this issue and know the fix?

 

Sounds to me like you have an electrical problem. Maybe a short with or near your switch.

 

But aren't the doors that control air flow actually controlled by vac?

 

Yes i believe so but always look for the simplist answer just like doctors do. And it is much simpler to fix an electrical problem in my opinion and it answers the problem. If your switch is shorting out, your doors are just getting the mixed signals. If not i'll admit i was wrong. Good luck

 

Ok thanks for the imput. I'll check the switch out. Some sifting through google results turned this up. I'm gonna look at it too just cuz it's a quick check. http://shallowbottom.wordpress.com/2...ir-vent-blues/

 

Wtf?

No, just no. The switch is an Air Switch.

Jesus.

OP, go hunting for air leaks either at the switch, lines, or at a vacuum line under the hood.

 

Ya 10-4 I've done a bunch more digging around online and apparantly this is a common issue on a lot of dodge vehicles. Low vac causes the system to devert to the defrost vents, so from what I've dug up I'm after either a bad check vaulve or a leaking line. Thanks...

 

Yeah, check one place for me.

Under the hood on the pass side, above the PCM kinda tucked away is a small 3-4 inch section of hose connecting 2 plastic lines.

When mine split my vents did some odd things.

 

From what I've been reading another symptom of this whole vac leak check valve thing is the cruise control will not hold speed, and my truck does that too. So anyway, I've pulled the little check valve outta the truck. It's not hard to find or get to (I'll post some pics when I'm done with this little project). The system still had vac in it when I pulled the valve, in spite of the truck having sat without running since yesterday afternoon, so it can't be leaking anywhere else, at least not very quickly. The odd thing is that the valve seems to be working. I can only blow through it one way. Maybe it's just weak?? I dunno. I guess for 8 buck I can try another one and see what happens.

 

Under the battery is a vaccum line that is known to rot and break. When this fails it is known to produce the symptoms you've described.