2010 Sierra Radio noise

[dsr611]

This is the 2nd time that I have noticed this noise and wanted to see if anyone else has noticed it or what it could be.  After getting home yesterday and opening the truck door and the radio shutting off, I could hear what sounded like the radio trying to eject a CD from the CD player (this is the AM/FM/CD/XM radio in a 2010 Sierra).  I turned the key back on and off and it was still making the noise.  After pressing all the buttons on the radio, turning it on and off (with key on and off), etc, it still sounded like a CD trying to eject.  I finally pulled the fuse for the radio and it the noise stopped.  Put the fuse back in and there was no noise coming from the radio.  The radio has never had a CD put in so I know there's not a CD in it.