Trailer Turn Signals and Brake Lights Not Working on a Trailer Towed by a 2004 Nissan Titan

Question:

i have a 2004 nissan titan, i have running lights that work on both sides of the trailer and a blinker,brake light on 1 side of trailer that works.. but my problem is the brake or blinker on the other side of the trailer does not work..took it to local dealer they replaced 2 fuses which gave me blinker-brake light on that 1 side but still do not have blinker-brake light on the other side they tested circuit said it was good on the truck...so what do you guys think the problem may be

asked by: Bo T

Expert Reply:

Since the shop replaced some parts and tested the circuits, it sounds like you have a ground issue on the trailer side. First, make sure that the vehicle side and trailer side connectors are clean and free of any corrosion. Corrosion can build up on the pins but also in the backs of the connectors where the wires attach.

Next, make sure that the main ground from the trailer connector is attached to a clean metal surface. Then do the same for the trailer lights. If you recently added a plastic license plate frame that mounts between a tail light and the trailer frame, that can also cause ground problems.

The connector you referenced, # N40975, is for a 2004 Nissan Titan that did not come with a factory tow package. The fuses fully activate the connector. You can check your truck for these relays by consulting the owners manual for their locations.

expert reply by: Michael H