Thanks you guys for your input!
I will start with checking the driver seat sensor but from what you guys are saying it looks like it has to go to the dealer. Perfect timing since I also cracked my sideview mirror (hoping to find a cheap replacement because I didn't realize how hard finding one with the turn signal was) and I am in the middle of moving. I didn't think about using Onstar for the trouble code. Too bad I don't have it anymore.