Right Side Trailer Lights Do Not Work on Trailer Towed by a 2014 Nissan Titan  

Question:

Helpful Expert Reply:

To determine if the trailer light problem is with the truck wiring or the trailer the first step is to test the truck side trailer connector. Using a circuit tester such as # PTW2993 test the pins on the connector while someone goes through the various light functions.

If everything checks out ok on the truck side, then that indicates a problem on the trailer side. If the trailer connector has some functions that are not working the problem is on the truck. Use the truck owner's manual to locate the fuses/relays related to the tow package wiring. To check a relay the best way is to use a known good one in place of a potential bad one.

Since the issue is just on one side of the trailer, it is not likely it is a fuse or relay problem. It could still be a wiring issue though and since the truck is new, I would take it in to the dealer under the warranty.

If everything works fine on the truck side, then you can move on to testing the trailer. First make sure that the trailer connector is clean and free of corrosion. Next make sure that the main trailer connector ground and the grounds for all of the lights are attached to clean and corrosion free bare metal surfaces.

Inspect the wiring to the right side of the trailer and look for any broken or loose connections and repair as needed.

If the trailer has a tilt bed, folding tongue, or aluminum frame, or you recently installed a plastic license plate holder between a light and the trailer frame, any of those things could cause a ground issue. Running jumper wires from the light grounds to the main trailer connector ground can help.

expert reply by: Michael H

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