Troubleshooting Running Lamps and Brake Controller Output on Trailer Towed By 2014 Ram 1500

Question:

Okay, I have a 2014 Ram 1500 Big Horn with factory trailer tow pkg. My trailer running lights are not working, No voltage at either 7pin or 4 pin connector. The stop and turn signal lights work as they should just no running lights. I borrowed a car hauling trailer from a friend last week and never could get the trailer brakes to work also trailer brake warning light on dash was on and running lights worked kinda had to do alot of wiggling of 7pin connector. I have checked practically every fuse in the fusebox under the hood and found nothing blown any suggestions?

asked by: John C

Expert Reply:

According to the owner's manual, the fuses in F11, F29 and F30 are the ones you'll want to check.

If the fuses were okay, then the most likely culprit is the trailer connector at the rear bumper of the truck. You should be able to remove the manufacturer harness from the rear of the trailer connector by sliding the gray locking tab and pulling firmly on the plug. Then, as a helper activates the running lights on the truck, take a circuit tester like # PTW2993 and probe each contact on the factory plug (Called a US Car Connector) If you find on pin that lights the tester, you're good. Then, have your helper pull the manual brake switch on your brake controller and hold it while you probe each pin until you find a signal. If these two pins light up the tester, you've confirmed that the trailer connector is bad and should be replaced. I'd recommend going with # HM40975-11933.

If you get no signal on any of the pins while the running lights and/or the brake control manual brake switch is activated, then trace the tow package harness toward the front away from the rear bumper, look for another connector you can detach and test or for broken or shorted wires. If you can't locate anything wrong at that point, then the problem exists in the tow package wiring somewhere between the rear of the vehicle and the fuse panel. At that point, you'll probably be best off having a mechanic look at it.

expert reply by: Mike L