It could be just a fuse. Check the Rear Underseat Fuse Block, changing the Drive Door Module (#10) fuse may help. Look at the silver-colored band inside the fuse, if the band is broken or melted, replace the fuse. Be sure you replace a bad fuse with a new one of the identical size and rating.
Please note, this is only a suggestion, not a diagnosis. If this isn't the issue, you may want to take it in for a quick inspection.
For your reference, this information is also available in the owner's manual on pages 5-95 through 5-106. A digital copy of the manual is available at the GM Owner Center at: GM Owners Center - GM
. The GM Owner Center is free to join and offers owner's manuals, stores your service records, dealer appointment scheduling and many other features.
I hope this information was helpful.
If you have any additional questions, please feel free to contact me.
GM Customer Service