One day everything worked fine and the next day air would only blow out the defrost and bottom vents - no air comes out the dash vents. There's been a faint rattle in the dash for years and I think something on a damper was loose and finally wore out. I have 27" vacuum at the pump and all the way to the A/C control block. I can take my vac. pump and apply vac. to the branch lines and still can't get air out of the dash vents and the yellow branch line appears to have a leak. All the branch lines will suck down to ~30" except the yellow one - it will only suck down to ~20". I think the problem is definately in a damper or servo. Can anyone give me some clues and tell me
how to get in there? I pulled the cluster bezel and started taking out screws in the top dash cover but I don't know where all the screws are or if I'm even on the right track. Is vacuum on the yellow line supposed to open the dash vent damper, or which one? Does the entire dash have to come out or what?? I haven't gone too far yet and don't want to break it. Any help would be wonderful and I'll be indebted forever! TIA! Craig

 

This is a problem on these trucks. There is a TSB on it. The vacuum pump leaks oil into the lines and causes the rubber diaphram in the actuators to deteriorate.
Happened to my 96. There an actuator just above the accelerator pedal, slightly to the right, mounted vertically on the heater box. It must be replaced.
The TSB says only 95 and 96, but you know how that goes.
http://dodgeram.info/tsb/1996/24-16-96.htm
http://dodgeram.info/tsb/recalls/720.htm

Pic of the actuator, looking up from the driver's side, above the go pedal:


Chris

 

Thanks very much! I see it has a yellow tube - the branch I think is my problem. I'll check mine out in a few. Craig

 

Yippeeee - that's it! That's the leak I was looking for and it has oil in it. I'm going to get a new one this AM. craig

 

If you have oil that far down you are in for more than an actuator.

 

I figured this isn't the end of it but it's fixed for now! Craig