2002 Pontiac Grand Am faulty door switch?

I AM WONDERING IF I HAVE A FAULTY DOOR SWITCH BECAUSE THE DOME LIGHT STAYS ON. THE DOME ITSELF HAS 3 SETTINGS, ON-DOOR-OFF. WHEN ON DOOR SETTING, THE LIGHT SHOULD COME ON WHEN THE DOOR IS OPENED AND GO OFF AFTER 10 SECONDS HOWEVER IT STAYS ON CONTINUOUSLY. IT WILL GO OFF AFTER 20 MIN. BECAUSE OF A BATTERY PROTECTION FEATURE. EVERYTHING ELSE WORKS FINE SO I AM NOT SUSPECTING A BODY CONTROL MODULE? SO, HOW DO YOU CHECK FOR A BAD DOOR SWITCH, AND HOW DO I FIGURE OUT WHICH DOOR IT IS? I HAVE TOOLS JUST LACK OF KNOWLEGE. ALSO THE DOME LIGHT COMES ON SOMETIMES INTERMITTEDLY WHILE DRIVING IN THE "DOOR" SETTING. THANKS