Trailer Running Lights Not Work with Wiring Harness for a 2010 Nissan Titan

Question:

I installed wiring on 2010 Nissan Titan XE. I installed the 3 relays, but the parking lights on my trailer are not working. The brake lights and the turn signals both work fine. I checked all the fuses that were labelled for the trailer, they were all fine. The wiring connection in the back is tight.

asked by: Dan

Expert Reply:

There are some things you can check to determine what the problem is. First, in the vehicle and trailer side connectors, check for any dirt or corrosion that may be causing a bad connection and clean it out.

If the trailer has a lot of lights that use the running light circuit, it could be too much power draw for the system and the wiring on the vehicle is not allowing it to draw power. Use a circuit tester like # PTW2993 to test the 7-Way without the trailer connected to see if the running light circuit is working.

The 2 small relays are for the turn signals and the large one is for the 12-volt circuit at the 7-Way. It is possible that there is a running light relay that for whatever reason is missing from your truck. You will need to contact a Nissan dealer for this relay.

expert reply by: Michael H