Interior lights pop on when they aren't supposed to correct?
Ok, pull the drivers door panel. Go into the door up by the handle there is an odd black plastic dealio on the handle with wires going to it. Green and white or green and black as I recall. Unplug it. Leaving door panel off, see if the symptoms persist.
The purpose of the switch is to light up the interior when the handle is pulled and door is locked. Courtesy feature that becomes a major pain when the switch goes bad. Being that the drivers door is the most used, it goes first.
00 Regal GS: All kinds of cool stuff.