[Greg Reimer 7376]

In about 1973,I worked for a gas station that had U-Haul rental trailers and trucks.You never saw junk until you saw their stuff. People used to rent a trailer, a clamp on bumper hitch, and wonder why the lights misbehaved. That was when bumpers had those big gas shocks suspending them, and continuity of ground wasn't too good to depend on. An auto electrician good enough to quickly diagnose and repair these issues that trailer lights can cause was enough of a rocket scientist that he didn't need to work there. Feed back through defective bulbs, sockets, and grounds would turn a saint into a drinking man. The suggestion to make sure all bulbs are correct for the socket is a good place to start. It might be necessary to remove all bulbs in the trailer, then re-install them one at a time until the glitch reappears. Good luck- it's probably something simple.