The brake lights on our tow rig are not working. Its a 2002 F-450. The lights don't work on the truck or at the trailer so that tells me the problem is in the truck. Both rear turn signals work so the bulbs are good. I checked both fuses on the fue panel slotted for brake lights (18 and 34 i think) and both fuses are good and there is current to them. The brake switch by the pedal is good because the electric brake box for the trailer reads when i depress the pedal. At this point i'm stumped. I'm hoping there is a brake light relay somewhere that could have gone bad or more fuses than just the two on the panel beneath the column. I would think that a wire was bad going back but i thought current for the brake lights ran through the same wires as the turn signals and operates the same bulb. Anyone have any ideas?