When a single light doesn't work, the problem is almost always either the bulb, the circuit breaker (or fuse), or the switch. The first and most obvious solution is to replace the bulb with a good one and, if that doesn't work, track down the problem through a process of elimination... 1) Test the bulb and, if necessary, change it. Be sure the bulb is screwed into the socket all the way. If you put a new bulb in the socket and it still doesn't work, test the new bulb in a working socket. 2) Remove the bulb. Turn the light switch on, and check to see if the socket is receiving power by touching