the lights in mine would stay on as well, but I also noticed that my drivers side door was not locking/un-locking by the electronic switches. A quick removal of the door panel and I found out that the latch assembly was actually broken in half, the latch still worked, but the electronics (which included the door closed switch) was broken off.
I un-plugged the wire to that, and it solved my problem, I can't use the electric door lock on that door, and the lights don't come on when it openes, but at least my battery doesn't drain...
My 98 is a 1991, so I don't know if yours has a switch, or if it's integrated into the latch like mine.
-Greg C.