You've probably already fixed your problem, but as AllDodge said, a good place to start is by popping the cover off the light and having a look. I had the exact same problem and replaced the light with the much cheaper Marinco version (control boards are interchangeable). Come to find, one of the wires in the connector between the light and harness just fell off in my hands. I haven't tested yet if that was my problem, but something to keep in mind...