sounds liek the bulb is bad/loose in teh socket/or a loose wire in teh opener to the socket. check to see if it is tight first, if it is, then chang ebulbs and see if another does it. if the new bulb does it then open the opener and check the wiring. unplug the unit FIRST!

You might try unplugging the unit, removing the light bulb and pulling out on the center contact in the socket. This sometimes gets bent down and doesn't make good contact.

Thanks for the information. Turns out it was just a loose bulb. As soon as I touched it, the light came on. I tightened it and it is fine. Weird that the bulb would suddenly be loose after 5 years though. I haven't changed it or anything.