Troubleshooting Trailer Lights On Sundowner Horse Trailer Not Working When Fuse Is Good

Updated 04/16/2025 | Published 09/08/2023

Question:

I shorted out a flood light on the back of my Sundowner gooseneck horse trailer and now my inside cargo lights, bith fluid lights and my enter light will not work. I checked the fuse in the goose overhead and it is ok. Nothing else is affected

asked by: James C

Expert Reply:

You are going to need to start testing your wiring with a Test Light # PTW2993 to determine where power is lost. I recommend starting by checking at the fuse you found. This will help you to determine which direction you need to mover on the wiring to determine if there was a short in the wiring which is causing the lights to not work before or after the fuse.

expert reply by: Bud M

Larry J.

4/16/2025

2010 Sundowner 4 horse NON living quarters trailer: does this trailer have a fuse box and if so, were would it be located? Thank you in advance.

Kate F.

4/16/2025

@LarryJ Hello Larry, I don't have the schematics to every trailer, my job would be a whole lot easier if we did. Your 2010 Sundowner 4-horse trailer (even though it doesn’t have living quarters) probably does have a few fuses or circuit breakers for the basic 12V systems like the interior and exterior lights, electric brakes, and the breakaway battery. Now, it won’t have a big fuse panel like an RV, but you’ll still want to check a few common spots. Start by looking up front near the trailer tongue, right around where the breakaway battery is mounted. There’s often an inline fuse in a little weatherproof holder close to the battery or breakaway switch. If your trailer has a tack room or a front storage area, check near any light switches inside there; sometimes they tuck a small fuse block on the wall or behind a panel. Another good place to look is under the trailer frame, specifically for a black plastic junction box where the 7-way plug wiring branches off. That box may contain fuses or just terminal connections. And finally, Sundowner sometimes uses simple inline fuse holders right on the wiring for the lights themselves, so tracing those wires might lead you to what you’re looking for. I hope this helps, let me know where you end up finding it.

Larry J.

4/16/2025

@KateF : Thank you for the quick response I assumed? it did have a fuse however some were saying no. I thank you for this information hoping helps me with the running lights/marker lights issue. Thanks again

Kate F.

4/16/2025

@LarryJ Trailer wiring is such a fun game. I got sick of fixing the wiring on our boat trailer so I ended up just ripping it all out and putting all new in, no issues since then! If you have any other issues or questions along the way, please feel free to reach out. Good Luck =)