04 GC Overland. I thought I might have had a blend door issue but now I'm not so sure. After shutting the car off for approx 2 minutes (timed) I hear a creaking/groaning movement sound as though the blend doors are going through a timed cycle, opening and closing behind the glove box or somewhere behind the dash area. This noise only happens when the engine is shut off and after like a minute or so. It is so loud it can be heard way outside the car with the doors and windows shut. Under normal operating conditions (accessory on or engine running) there is no noise whatsoever no matter what I do with the system. The system directs the proper heat or A/C to the proper vents depending on the flow of air I choose. Cold is cold and hot is hot. That all seems to be working as designed. So, I removed the glove box, removed the blend door actuator and the first test was to see if the white blend door rod rotated freely and has about 90 degrees of rotation. It is as smooth as silk and has a hard stop at each end of approximately 90 degrees of movement. No sounds at all coming from it when I manually rotate it. All that seems to be fine.

So that leads me to wonder if it's the recirculation door instead? That too seems to be working fine as best I can tell and no noise comes from it either when I activate and deactivate it.

My last question (or is it my first?) is whether or not there is something unrelated to the HVAC system in its entirety that could be causing this noise behind the dash. I know they have a tendency to cram in as many things as possible behind the dash but nothing I can think of that actively goes through a cycle three times once you shut the engine off.

I've attached a link, assuming it allows me to, of the sound.


Thoughts? TIA!

I have a 99 Grand Cherokee, turn it off and wait for the creaking noise. Mine does it every time. Bought it used, still trying to figure out the pandora's box of the blend doors, recirc doors. Started tearing into mine and found a popsicle stick propping the recirc door closed. Wish I could be of sound technical advice but mine seams to originate from the recirc door area.

Yeah, they all do that.

Well, the ones with the premium climate control (the two digital temp displays), anyway.

My '99 makes the noise as well and exactly when/how described. My blend and mode doors also seem fine but I know my recirc door is broken so that is probably your issue as well.

The noise itself is not normal, obviously, but when it occurs I believe IS normal. It's trying to recalibrate because it senses something is wrong based on actuator motor travel.

You can check the HVAC unit for fault codes:

15, 52, 54, 56. I guess that means the 15 is current and the others are historical. And by temperature door, I assume they mean blend door?

10KMistake, if you need to replace that popsicle stick make sure you only use the Mopar branded one................................

Correct

Guess I better start practicing my Dremel skill tools. On a separate note, I watched a YouTube video of a guy doing it with a welding gun tip attached to a soldering gun and I thought that was a unique technique too.

The Mopar one is on national back order due to the pandemic. I am keeping the faith it will be available by winter.

Better hurry up and wait then, because if you use an off brand stick, it can make your muffler bearing go bad....

I just replaced my muffler bearings. Wasn't too bad of a job but you need skinny arms to fit inside the straight pipe. Now to swap out my winter blinker fluid for the summer stuff.

Bought a case of it at Wally Mart. Had to return it, bought it for the left Blinker, needed it for the right.

Ha ha, this is getting out of hand...