Climate Control Fan Speed Problem

rcgolfer · March 15, 2004

Anybody have any experience with the Yukon automatic climate control?

When I set the system controls to "auto" the fan is supposed to slow down as the temp gets close to the pre-set value. Worked right for the first 65K miles. Now the fan always stays on the highest setting. Something broke... Now I have to adjust the fan speed manually to get it to slow down.

I would appreciate your thoughts if you have any experience, as I don't know where to start.

citydriver · March 15, 2004

Inside temp. sensor ..MAYBE

zshumo · March 15, 2004

is this a problem w/ heat and A/C or just one?

rcgolfer · March 15, 2004

Problem is there on both heat and a/c.

Inside temp sensor is a strong possibility, I think, as everything in the system works normal except the fan doesn't slow down on auto - a/c works, heat works, heat and a/c temp control works, and blower speeds work right if controlled manually.

Can you tell me where the inside temp sensor is located? I am assuming I can diagnose with an ohmeter as it will be an open/close thing.

March 15, 2004

I apologize for asking what seems to be a stupid question,,,but.

Did you try hitting the AUTO button again? If you change the fan speed manually it will not go back to AUTO unles you tell it to, even if you change the temp setting. Under the temp indicator it should say AUTO.

rcgolfer · March 15, 2004

Ain't it the case, so often, that we overlook the obvious. In this case, though, operator error is not the problem. There is something definitely wrong with the fan speed control.

citydriver · March 16, 2004

Not sure about the location of the internal sensor w/o lookin in the manual under COMPONENT LOCATION....BUT sometines there r what looks like a bunch of holes on the dashboard and the sensor is under there...thats just a guess

chevroletmb · March 16, 2004

the internal temp sensor otherwise known as the aspirator

is the small speaker looking thing right above the drivers head

in the headliner. most people mistake is for an onstar speaker.

it has a small fan that draws air in to the sensor

rcgolfer · March 17, 2004

WOW, the plot thickens!!!

As you indicate, I thought this was the OnStar speaker. I have had an intermittent buzzing noise in the cabin, mostly when the car is in cold weather, before the cabin warms up. It was there for about three years. It gradually got worse, and I tracked it down to this device. I pulled to cover off the device and pushed it back up into the headliner, then put a small piece of sytrofoam over it for sound isolation (obviously, I am not a OnStar subscriber) and set the cover back into place.

Now I am going to have a new problem: when I undo what I have done so that my fan works correctly again, I am going to get that nasty buzz back. Anybody had to deal with that problem?

Thanks!!

rcgolfer · March 17, 2004

Oops. brain cramp - I meant foam rubber, not sytrofoam.

I suppose I have to replace the aspirator to get it quiet. Do I need to pull the headliner to do this, or is proctocsopic surgery possible for getting at the connector and re-mounting the device?

GDN · March 18, 2004

As long as the fan in the headliner hasn't quit you should be able to fix this yourself fairly easily. When I first got my 2003 with the climate control I wanted to see what was under that grill in the headliner - so I pulled it off. I thought it was pretty cool when I discovered the fan in there - I put it back on, curiosity satisfied. That is where my problem began and it sounds a lot like yours - my auto air would always stay on high.

The problem is that the grill doesn't just push back into the head liner - it has to clip into the fan itself. The fan has probably slid off of the hole and is no longer pulling cab air into the cavity where the temp sensor is. To fix it I was able to pull down on the headliner enough to push my hand in to reposition and hold the fan over the hole and then properly attach the grill to it. No more rattles, and a fixed climate control.

If you're still curious as I was if the fan was working once again - I unfolded a paper clip and stuck it through the grill until I could hear the fan blade hitting it - its been working like a champ ever since. Do this test at your own risk of damaging the fan.