Troubleshooting Trailer Stop/Turn Signals Not Functioning When Running Lights Still Work

Published 06/30/2016

Question:

Hi I am running a 6 by 10 utility trailer from an F250 pickup truck 2005 and both turn signals and brake lights stopped working but all the running lights are working what could be my issue

asked by: Jim

Expert Reply:

Since they both stopped working at the same time and the circuits you mentioned draw more amperage than the running light circuits the issue sounds like a bad ground for the trailer lights.

Make sure that the trailer and vehicle 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