Hi guys, there's a little speaker grille looking plastic piece above the driver door that buzzes continuously when the key is turned on, and when running. Turn the key off and it takes an extra second for the buzzing to die off. Any ideas to what this is and what's causing the buzz? Mods, feel free to move this if this ain't the right forum.

 

Should be part of your OnStar. you should be able to turn it off with button on mirror.

 

Thanks for the reply. Here's another possibility I have found... "Interior Ambient Air Temperature Sensor"

 

I remember a post about this but I can't seem to find it. You are on the right track though. Maybe try some compressed air to blow the dust out of the sensor?

 

It has nothing to do with OnStar. You have the Automatic Temperature Control (ATC) system in your truck. This is the interior ambient temperature sensor.

And as Gary has suggested, if it is buzzing, hit it with some compressed air to try and clean it out.