MPT

Has anybody had a problem with the air flow stuck on a direction and won't blow air on any other setting? I can switch flow settings to all directions- floor, dash, defrost, etc, but only air flow comes out of defrost! I own a 1997 Ram 2500 4X4 diesel.

patdaly

Couple of possibilities, first, have you done any work on the drivers side of the engine, fuel filter, etc?

If so, good possibility that you have pulled the vacuum line loose at the T on the cowl top, drivers side. You can also check to see if your cruise quit working, that would also indicate the vacuum source was lost.

If you have good vacuum to the head, it could also be the mode door vacuum servo, fairly easy to change, see this thread.

https://www.dieseltruckresource.com/...-issue-318758/

torquefan

There was a recall at one time, but I think it was only certain 95 or 96 trucks. It involved oil migration from the vacuum pump through the lines and into vacuum-operated accessories like the HVAC actuators. The only failed vacuum actuator I've ever seen on these trucks failed because it got engine oil into it, which swelled up the rubber diaphragm and ruptured it. Anyway, if it turns out to be a failed actuator, have a good look at it to be sure it's not all oily inside.

MPT

Hey patdaly, I found out that's exactly what was wrong was that I must've pulled the small black vacuum line out of the rubber boot located just under the hood rubber seal and between steering pump and fuel filter. Now air direction modes all work, and guess what? my 4 wheel drive light comes on again and now front wheels engage! (I didn't mention about my 4 wheel drive not engaging because I had no idea it would be related to the same problem!) One thing to check now is to see if that remedies the cc not working because I haven't had time to take it out on the hiway yet. Thanks a bunch you guys! I'm a happier Dodge Ram owner now!

patdaly

Yep, that will fix your CC as well.

LOL, I think we have all done the same thing at some point in our trucks life......... now I just glance at the T anytime I work on the drivers side of the engine, it becomes sort of an OCD thing like patting your wallet to make sure it is still there.