Vacuum problems, maybe?

JoeTheCarGuy

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Sep 15, 2017
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Alabama, United States
On my 04 the HVAC vent selector doesn't work it is currently stuck on the dash vents, no defrost, no heater vent. I know this is a vacuum operated switch or selector. What is the main culprit usually, selector, vent door motor, something else?
Also, the cruise control functions, but not properly. I set the speed and it will creep up, sometimes 10 mph over the set speed (even on straight level roads), then return to set speed and then creep back up again. It continues to do this until I disengage the cruise control. Then the engine wants to idle wildly, like 3000-3500rpm.
Could these two issues be related to vacuum? Could the cruise/idle issue be the idle air control valve? I've removed it and cleaned it right after I bought this Jeep back in the fall.

Thanks in advance!

JV
 
Last edited:
Haven’t had to troubleshoot cruise yet, but in my 05 LJ when I first got it it wouldn’t switch HVAC vents as well. My problem, to the right of the accelerator pedal there was a cluster of vacuum hoses on the firewall inside the Jeep that were close to unplugged. Just seated them back and mine were fine.


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