Rear Ac Unit Squeal?

tomcatinva · December 7, 2007

I have a 2004 Denali XL that I have had "issues" with the rear AC unit squealing when it is on. When the noise starts I turn off the rear AC unit and it goes away then I just turn the rear AC back on and it's fine for a while. Has anyone else had this issue? I have been back and forth to the dealer and no fault to them they can't seem to replicate the problem as this is an intemitant issue. It sounds like something metalic rubbing against each other, you know almost like the finger nail accross he blackboard sound... I did notice (or at least my kids told me) last night while driving home in the cold when I turned the rear heat on for them they said that there was no heat coming from the middle vents but the fan blower was running and the far rear vents had air coming through them.

Anyway if anyone can offer some assistance it would be great...

Thanks,

TomCat...

tomcatinva · December 13, 2007

Anyone have any ideas? It's like listening to someone drag their fingernails accross a blackboard...

Thanks...

TomCat

Mlshelby · December 17, 2007

Expansion valve?

tom9489 · December 17, 2007

Almost any squeal will be coming from the blower. I had a 1990 Suburban with rear A/C and had a bad squeal. The problem was that the blower motor had shicfted slightly to one side, causing the squirrel cage blower hit the plastic case. Repositioning the blower motor solved the problem. I don't know what kind of blower you have on the 2004, but it is definitely of a different design than my 1990 model. That said, it still could be a case of the blower wheel hitting the case. My squeal was intermiittent, too, and was worse on high speed than low speed.

Good luck.

tomcatinva · December 18, 2007

Thanks for the ideas I will get my local GM specialist to take a look, because if I get into it I know I will be going there with more than just the original problem...