Roamer1

The dash vents on my truck haven't worked right since I bought it about 6 months ago. I only get a trickle of airflow, no matter where I set the controls. With temps over 100 now, it's starting to bug me. Is this a common problem? Anybody know how to fix?



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jadocs

Take it back to the dealership.

CarlJensen

Vents will default to defrost if you lose vacuum to the system. Check vacuum. Look for a broken line or punctured/cracked line or fitting. At the firewall is a common problem.

patdaly

I am assuming you can feel it switch from dash vents to defrost, if not, then look for your vacuum leak.

If you can feel it switch, a couple of things, plugged evap core ( happens ), or a fan motor not working properly, mine will run at a lower speed until I what it soundly, then it takes off. You might check that out.

Roamer1

Thx for the replies & suggestions. I do get some airflow through the dash vents, but barely any. And I hear flaps behind the dash trying to move around when I tweak the control ****. But all I ever get is partial dash flow. Most of the flow is going to the floor vents. I guess I'll poke around under there and see what I can find. I was just wondering if there's a common part that usually fails when this happens.

patdaly

Doh, I forgot about the blend door issue, do a search.

Fairly common, had it on my Jeep, but never on a Ram.

Roamer1

Reading up on the blend door problem, thanks. Sounds like that might be my issue.

CarlJensen

Another common problem. Check out the replacement parts to replace plastic.

http://heatertreater.net/

jj3500

this happened on my 2001. not sure of the specific fault, but it was related to a vacuum line dried up and cracked.
i had no 4X4 and also it tied in with my cab vent/temp controls.

was a simple vacuum line swap, all is well now.

Roamer1

After lots more driving with the AC on, it appears the temperature "blend door" is not my problem. I can control the temp just fine. What I can't control is where the cold air comes from. It seems stuck on the floor vents. Time to check for vacuum leaks, I guess!

Busboy

Get down on the drivers side floor and look behind the plenum, part way up you will see a vacuum actuator with two vacuum lines going to it, either one of them is off or you need a new actuator as part of it is leaking internally.

Roamer1

Thanks Busboy, I'll check that out ASAP. :-)

Busboy

The 2 vacuum lines are yellow and red, the yellow one should have vacuum and the red should be vented to allow the actuator to move full over. Try disconnecting the red line from the actuator and see if you can hear a vacuum leak, if so the actuator is leaking internally. If you have a vacuum hand pump it makes troubleshooting easier as it's easier to hear leaks, just hook it up to the yellow port with the red line open apply vacuum and listen for a leak.