how much do you know about electrical? well i just looked under mine and i can see the plug on the driver side under the truck by the bumper. you can unplug it there and put your lights on and see if there is power at the plug (should be the brown wire). use a test light or meter. make sure you have a good ground if you use either to test. if there is power at the plug, then your problem is from the plug to your lights. or a bad prong on the plug. if there is no power follow the wire back to were it connects to the passanger side and see if you can spot a crack or breek in it. if there is a crack in the coating the inside of the wire could get wet and "be nomore". since you have trailer wires my guess is thats where the problem is. lots of people use the push on splices and the wire just rotts away at that spott over time. or if it's the plug in type could be there. let me know what you find.