The driver-side power window of my 2002 Pontiac Montana stopped working. How do I remove the door panel to troubleshoot this?
The best thing you can probably do is buy a repair manual ($20 at an auto parts store). These will give you the basics on where all of the connection points are. Its also worth it to buy the little tool used for popping the panel retainer pins.
The switch panel you should just be able to pry out of the top - very thin screwdriver and just be careful not to mess up the edges. So that you can test without pulling the whole panel (you’ll need a voltmeter). Somewhere in the vicinity of the armrest/interior handle are a couple of bolts. The rest of it should be those plastic push pin retainers for which you’d want the panel tool. All of that if memory serves.
This panel is held by what mechanics call “Christmas Tree” fasteners. Trouble with the Montana (or the Venture) is they have turned out to be "one time use’ that is they don’t hold good when re-used, get about 15 new ones befofe you start.
Get the window switch out of the armrest first. The image is not perfect in my mind but there is almost always screws holding the panel at the arm rest (look underneath). Now I may just be a dumb a**, but I always found going deeper into the window “innards” much more difficult than lets say a full size GM pickup. The window "guts’ are in a some what modular setup. It’s trying, and things must be massaged to fit well, not my favorite motor and regualtor to do. I have done about 30 of them,pretty common.
Really make sure it’s not the switch, first.