What needs to be repaired if dome light goes on and off when hitting bumps?

When I have a door ajar, I get a message on the dash board that says Door Ajar in red. That isn't happening, just the dome light in the front next to the rear view mirror will go on and stay on for 15-30 seconds and then go out or hit a bump and it will go out. Other times while driving if I hit a bump it will come on and then go back off after 15-30 seconds.