Troubleshooting Trailer Running Lights and Tail Lights

Question:

We brought the trailer new last year and have only taken it out camping once..I dont think they have ever worked ..I have one pin on my truck that dont have power on it I have checked it ....I think this could be the problem..

asked by: Charles J

Expert Reply:

The first thing that I would check are all the fuses associated with your trailer taillights and make sure that they are installed and functional.

I then would look at the vehicle connection at the trailer connector and make sure that all the wiring to the connection points are in-tact and that the pins do not show any signs of corrosion or damage. Any of these issues could definitely be causing the tail lights to not function properly. You will want to use a circuit tester like part # PTW2993 to test the functions on your connector.

The connector tests fine, that means the problem is on the trailer and not your vehicle. Inspect the running light wire starting at the trailer connector back to the lights themselves. You're looking for any damaged or pinched wires.

If you don't have running lights on the vehicle's connector and the fuses all checked out then check the wiring going forward from its connector. Again looking for damaged or pinched wires. If the wiring harness has a converter box you can also test the wires before and after the box. If there is power before the box but not after, then you need a new harness. If this is the case let me know the year, make, and model of the truck as well as the type of the trailer connector and I'll recommend a replacement. If you still can't find the issue let me know and we'll keep troubleshooting.

expert reply by: Patrick R

Charles

1/1/0001

Patrick R.

8/22/2019

That failed pin would be where I would start for sure. It may help to refer to the attached help article to determine which pin is the issue and when determined, we can know what connector we will want to recommend. For example the 12 Volt Aux Pin (black) or the tail and running lights (brown) pin could be the issue but would also need to know if you have a 4-way, 7-way, etc. Happy to help from here once you have that information.