So...my map light worked fine with doors opened but when closed the switch was lighting up the lamp so I unscrewed and figure it wasn't touching contact . I unscrewed and attempted cleaning contacts when this black jumper ground wire pops out. I can't find where it gets reconnected. Apparently it's suppose to attach to an existing screw. Now none of the courtesy lights work. Map, under dash and back seat. Any help is appreciated.

 

What car are you working on?

 

All the courtesy lights work by connecting the ground side of the lamp. On my 98 the ground wire goes under one of the mounting screws.