I just bought a 2002 Chevy Suburban with 166,000 miles. There are quite a few things that need to be fixed. And here is one that I can't figure out...

Anytime the key is in the "run" position, I hear this intermittent squeak, or chirp, or grind, etc. It sounds like the blend door is moving, but its louder. It happens every 20 seconds or so, like clockwork. It always does it no matter if you are driving, idling, or engine not running with the key in the "run" position.

If searched and searched, and I cannot figure this out.

Can anyone help me with this one?

Thanks in advance!

 

Sometimes, isolating the area where the sound 'seems' to be coming from can be a big help.


Does this sound seem like its coming from underneath the dash, between the glove box and the stereo?


Does it seem to change note or frequency when you select a different discharge location on the HVAC controls (between floor, dash, front, etc.)?


Does your "key in ignition with door open" and/or "seatbelt unlatched" chime work as it should -- proper sound, intensity, and only at appropriate times?


Does this sound happen when the HVAC is set to off "O"?


Answers to a few of those questions might help us make more informed suggestions.

 

"seems" to be coming from behind the passenger airbag, or behind the glove box. Somewhere back there.

It doesn't matter which discharge location is selected. The sound frequency or pitch doesn't change. It doesn't matter where the temperature control is. It doesn't matter what fan setting is selected.

Chimes are working properly.

The noise happens even when the fan is set to "off".

The noise seems to be completely independent of everything else. Nothing I do changes the sound, pitch, volume, etc.

To me, it sounds like a blend door is grinding. But the blend door is working properly. All settings (floor, floor-dash, dash, floor- defrost, defrost) work properly, and the blend door is very quiet when it changes settings.

 

I have a similar "problem". Just subscribing here hear some answers.

 

you could disconnect the temp, blend, recirc actuators or hvac module and see if the noise goes away

 

How do you do this?

 

remove the glovebox, get your head in there and move the controls to actuator the blend doors....does the noise sound the same...if yes,
locate the electrical connectors and disconnect them one at a time until the noise goes away.