Troubleshooting Taillights on Barbecue Pit Trailer

Question:

I have a BBQ TRAILER and when I connect the plug to the truck, no lights. It has a little battery box on the trailer and one of the terminals has corrosion, would that be the problem

asked by: Leroy

Expert Reply:

I'm assuming you're speaking of the trailer taillights. Are none of the taillight functions working, or is it just one or two? If none are working, it could be a poor ground connection.

First check the point on your trailer tongue where the white wire grounds to the trailer frame. Make sure this connection is secure and that the metal of the trailer tongue isn't corroded. One good way to get a bullet proof ground connection is to undo the ground screw and sand a dime sized area around the screw hole down to bare metal. Sandwich a star washer between the trailer tongue and the ring terminal on the ground connection, then reconnect the ground screw. The star washer will bite into the metal, resulting in a super-reliable connection. Then, hit the ground connection with a quick shot of rust inhibiting spray paint to exclude moisture from the connection and to protect from corrosion.

If some but not all the taillight functions are working, use a circuit tester like # PTW2993 on the trailer connector on the vehicle while each taillight function is activated, this will help determine if the problem is on the vehicle or the trailer. If all the functions at the trailer connector work, the problem is in the trailer wiring, and you'll need to trace each circuit back from the trailer connector to each lamp. Look for loose connections and broken or pinched wires, and repair as needed.

If none or not all the taillight functions work at the trailer connector, the problem exists in the vehicle wiring. To narrow down the problem, it would help if you replied with the year, make and model of the vehicle and let me know if the trailer connector is part of the factory tow package or if the trailer connector was added afterward.

The corroded battery terminal you describe won't have an impact on the trailer taillights, but you should clean that up. I'd recommend you use some fine grit sandpaper to clean the corrosion off the battery post and terminal, then coat the post with a thin layer of dielectric grease like # 11755.

I've linked to our trailer wiring troubleshooting article, which you might find helpful.