i cant figure out why my heating controls on my 94dodge 3500 quit working. i can control the speed of the fan and the temp but not the directon of the air can anyone help me with this problem.

 

its a vacuum line problem. did it default to defrost?

 

^^^^ x2. Sounds like you lost your vacuum feed.

 

well awile ago it stopped blowing cold air so i figured it needed recharged. then the past 4-5 months when i have it on another control it always goes to winshield defrost everytime now i cant even get it off defrost like i always say i hate my dodge but love my cummins

 

Yeah you've lost the vacuum feed to your panel. Look for a black plastic line going into the firewall on the passenger side near where the A/C lines pass through. Follow that along the rim of the firewall over to the driver's side and check all of the connections. Mine came off a few times while working under the hood and I didn't know it.

If it's not off there then check at you control panel. If it's connected there then it's off behind the dash somewhere.

 

so when i fallow it to the driver side do i have to be looking in the engine compartment?

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if it were disconected somewere under the dash were would it most likely be

 

yeah under the hood.

There isn't really a "most likely" place if it's off under the dash. IIRC you can't even really see the line from the inside without at least taking the glove box out. You just have to take your time. Start outside though. I bet it's there.

 

well i look at it tonight and see if i can find anything

 

You'll find it. There is a vacuum T just above the brake booster. Mine always came apart there.

 

Also check where the line hooks to the vac. pump. Thats where mine comes off when I change the fuel filter. Like the others have said air will only come out the defrost if unhooked.

Does your ac clutch cycle? If not you might check your horn fuse (20 amp). Its also the fuse for the ac clutch.