Nebraska_Chevy

Okay, good to know. Thanks for the info. It's probably been happening for a long time and I just have never noticed it until now.

I didn't know the radios had cooling fans, interesting. Do you think this will remain an ongoing problem and is this fan a big draw on the battery?

I have a 2009 GMC Sierra SLE with factory radio and no nav. I noticed this a couple of days ago and again today, after I shut the engine off and radio off and opened the driver's door, I noticed what sounds like a faint electric motor running from behind or within the radio. Kind of sounds like a CD disc spinning, but there is no disc in the unit. The only way I could get that to stop was to pull the fuse for the radio. Anyone else have this issue? I'm concerned about what it may be and if it will drain my battery if left to run. Thanks.