07 Tahoe LT

While driving the other day, I noticed a humming sound coming from the onstar speaker above the driver's seat. I turned my radio and air conditioning off and could still hear it. I can also hearthis noise when I turn the ignition on but without starting the engine. It can be heard in the rear speaker asabove the back seat as well. I'm not well versed on electrical issues so I thought I'd see if anyone has heard of this before. I'll be taking it to the dealer soon. Thanks

 

That's actually a small fan that passes environmental 'data' to the HVAC system.

 

I'm wondering if it's possible for there to be a ground problem here because it seems at times, this noise is much louder than other timesand I haven't noticed it before.

 

Let me reiterate:

IT'S NOT A SPEAKER!!!

 

Have the dealer look at it. It is a fan and others have had the problem and it will probably be replaced.