Why are my Ford c max interior lights not working?

The Ford C-Max interior lights not working causes are corrosion and failed relay. The light bulbs will burn out eventually. If it becomes dim, You will have to replace them. They aren't too expensive, so they won't hurt Your wallet. Being able to see at night is key for driving down the road. Your lights need to be functioning or You may get into a crash. Some issues will arise at some point. A faulty wire could come about. Lights may burn out prematurely. Corrosion is very nasty to deal with. Blown fuse may come about. A failed relay means a failed light source. These issues need to be dealt with quickly.