Trying to tackle fixing the wild vents on my 2001 ram 1500 4x4. I've done many things in tracking down the problems in the vacuum system and have had no such luck fixing it. Some things I have done and found

1. One bad check valve. Replaced with one from dodge, the new one doesn't seem to hold a vacuum its more of a restriction in the system in one side. The other factory check valve holds a vacuum

2. Found the vacuum line running down to the CAD was broken causing a full time vacuum leak. I plugged it at the t-fitting - going to eventually get the posi-lok kit and do away with the vacuum system there.

3. Cruise control hasn't given me any problems, functions as it should.

4. I have replaced all the factory vacuum lines with new rubber vacuum lines, elbows and t-fittings except for what runs into the vacuum canister under the cowl, the cruise control line and the line that runs into the truck for the HVAC

Any suggestions on what I could be the problem?


Yee-Haw! Got it fixed tonight! I went to oreillys and bought 2 generic check valves and put into the system where the factory had them. The first one is right at the intake manifold, right before the line that goes to cruise control. The second one goes right before the HVAC control inlet to the firewall. Currently it works so good that I do not have the vacuum canister hooked up and it still holds under WOT, hills etc. The line for my 4x4 axle disconnect is removed since I will be installing a Posi-lok kit on friday.

Here's everything I found wrong on mine

1. One of the two vacuum lines on the CAD was broken. Full time open vacuum leak. I'm guessing that it is the line that holds the axle disconnected while in 2wd mode.

2. Last summer I found one vacuum check valve broken. The one closest to the intake manifold. Went down to the dealer and bought one replacement and did not fix the problem. I checked both of them and the one I purchased was not holding a vacuum like it should. I may be wrong, but both check valves must operate properly to ensure that the vents hold their position.

3. I broke some various vacuum lines on the engine. I bought some various vacuum lines and t-fittings and rebuilt the harness coming from the intake manifold with 2 new check valves.

4. Vacuum canister wasn't holding vacuum (Either defective or cracked line to it) Currently it is unhooked from the system and the vents are working just fine. I plan on taking the plastic cover off so I can get to it and test it.

I want to replace the line that runs into the firewall and goes to the vacuum control switch on the dash but that will be later on down the road.