Troubleshooting Trailer Turn Signals that Work But Not Brake Lights

Published 02/19/2016

Question:

have no brake light but have turn singles

asked by: THOMAS A

Expert Reply:

Sounds like the ground of your trailer is too weak to illuminate both trailer taillights at the same time and that is why the turn signals work but the brake lights do not.

Make sure that the trailer side connector are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.

expert reply by: Jameson C