Troubleshooting Brake Light Malfunction on Boat Trailer  

Question:

Helpful Expert Reply:

There are many reasons why when you hit your brakes the trailer lights may not illuminate. I recommend starting with checking the trailer connector on your vehicle for function using a circuit tester like # PTW2993. The brake lights will be on two different pins, one for the left along with the turn signal and one for the right with the other turn signal. Check your owners manual for any fuses specifically related to trailer wiring.

If you have power at this functions on the truck side, then I recommend next connecting your trailer and then checking the ground connection on your trailer frame. Make sure it is free of corrosion or debris and is metal to metal. Next check the ground connection at your trailer's tail lights. Some times the ground is a separate wire and other times the lights are grounded through the mounting bolts. Make sure these connections are bare metal to metal as well. You may want to put some dielectric grease # 11755 at these locations to keep moisture out and keep corrosion away. Check your connections with the circuit tester. If you have incandescent bulbs, it may be time to replace the bulb or the fixture if you have power to the light fixtures on the correct wires. If you don't have power on the wires, you will need to trace them looking for a short. First visually inspect them for missing insulation or pinch and then test by probing through insulation with circuit tester to find the short.

expert reply by: Jason S

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