There’s the Rub
Owners of 2007-2013 GMC Denali, Sierra or Yukon vehicles may comment that one or more of the doors do not lock/unlock when activating the power door locks. The condition may be intermittent or constant. The cause may be that the door locking button is hanging up on the window belt inner sealing strip within the door. The inboard seal material may rub on the button.
It is not necessary to remove the door trim panel. Verify the condition by removing the door locking rod knob. Ensure that the locking rod is in the unlocked position.
Use a flat-bladed tool to disengage the detent tab and then remove the knob by pulling up. Verify interference of the door lock button to the sealing strip by visually inspecting the area behind the button for sealing strip material protruding into the door lock button area.
Use a trim stick or suitable tool to reposition the sealing strip to the outboard side of the down-standing tab. When reinstalling the lock knob, push the knob down until the detent tab touches the locking rod opening cover. Push the detent tab in to lock the knob to the locking rod.