The genuises that installed my alarm somehow left the dome light (in the center of the car, not the ones up front) unplugged or something, so they dont turn on anymore. Where do i even start to look for the wiring for this?

 

try tightening the screws that hold it up, I replaced my headliner and didnt tighten those scre and it didnt work, Something to with it properly grounding via the screws