AC is possessed!

Joined
Mar 13, 2018
Messages
52
Location
Forney, TX, USA
My 04 LJ ac is on its own program. Regardless of where the selector is positioned, the air blows out of random vents. Sometimes the dash vents, sometimes the defrost vent....and it moves around on its own. I'm sure there is an easy fix but not too sure what it is. Anyone have an idea of where to start?

The temp control works fine as does the speed control. I was thinking that the vent damper was stuck but then it started going from one vent to another.

Thanks in advance!!!
 
Sounds like you've got a vacuum leak somewhere under the hood. Often times it's the vacuum line right under the battery tray. The vent selector is controlled by vacuum, so when a vacuum line goes bad, you often times get vents that act wonky, get stuck, etc.
 
Awesome!!! Thanks Chris. I'll check it out tonight after work.

No problem! Inspect carefully, it's almost always due to a leaking vacuum line, but sometimes you have to really take your time looking to find it. Trace the lines on the intake manifold, down under the battery, etc.

This is the very first place I would start.
 
possessed?.....You could try pouring 'holy water' into the radiator hehe
 
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If your vacuum lines are ok, it could be the switch. It is fairly easy to replace and costs about $30-$40 for the Mopar part from Amazon.
 
We had visitors last night but I did find a connector on the vacuum lines that needed to be replaced. I changed the one but didn't "fix" the issue. I'm sure there are more. Pretty sure it's a vacuum line. I noticed that it changes with more rpm.

It's looking like Saturday will be the day so I can spend some quality time without interruption.

If that fails I will go to the switch from Amazon. Thanks for the tip.

I tried the holy water but it just laughed. lol......
 
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You can undo the brake booster vacuum line and blow smoke into it. If you have a vac leak smoke will leak out of it. I knew guys that had cigars in their tool box for this very reason.
 
:D Great job...now you can sit back and admire your work lol...nothing more satisfying than fixing something.:campeon: