1996 Ford Thunderbird Lights

Interior problem
1996 Ford Thunderbird V8 Two Wheel Drive Automatic

I just resently purchased a 1996 thunderbird and the jerk that owned it before me did something to the interior lights so that they never go off. Even when the door is closed. I know that its not the switch because I recently brought a new one and installed it and it still does the same thingHow do I get them back to normal.