its probably the switch in the door jam. the fix couldn't be simpler. either try spraying some wd-40 into it and push it in and out a bunch of times, or just go buy a new one for cheap. i'm sure that's all your problem is.

-Dan
1998.5 SVT "Black and Blue" #5292
See here for MOD list.
"Washing your car to make it rain does not work."