Trailer Lights Cut Off When Coupled to the Tow Vehicle

Question:

my trailer lights work just fine when I connect the harness to my truck. However, as soon as I lower the trailer coupling onto the ball, they QUIT!!! Ive cleaned my ground and changed out the end. Ive inspected the wires that I can access and have found no bare wire or signs of corrosion. I replaced most of the wire a year ago and all worked fine when I parked the trailer. Not sure what to think. My truck is a 2018 GMC and the trailer is a Shorelander atv trailer.

asked by: Mark

Expert Reply:

I know that you said you checked your grounds but the issue you are having is very common with a weak ground. Therefore, in order to fix this issue I recommend using a junction box like part # 38656. Once you have this installed you can then run the grounds for all of your lights and the trailer connector to the ground terminal inside the junction box, then to a single point on the tongue with 10 gauge wire part # 10-1-1, a ring terminal part # DW05705-1, and a self-tapping screw part # 101131802.

If the above does not fix your issue then you may just be better off taking your trailer into a local service center.

expert reply by: Conner L