2008 Chevy Silverado Dome light does not come on when unloc

It will be inside the door panel. The door panel is held on with plastic clips and usually some hard-to-see screws (behind door lever, behind arm rest, etc.). The switch itself is usually held on with plastic clips. Easy removal/installation. Other components may have to be removed to gain access though such as the window motor, lock assembly, etc.

Yes the doorjamb switch is inside next to the door latch and it should only be held by a couple of screws