Troubleshooting Stop/Turn Signals Not Functioning on Trailer

Question:

Rewired trailer w/4pin connector. Running lights work but brake and turn signal not working. Color coded same to same. Had to dual wire brown. Any suggestions. Did check 4 pin on truck and ok with tester.

asked by: Rich R

Expert Reply:

Since you tested the 4-way of your vehicle we know the problem is in your trailer wiring.

The first place to check is the grounds of the taillight assemblies. Trailer lights usually ground through the mounting studs and they, too, will need to be attached to a clean and corrosion free bare metal surface. On the trailer side connector, make sure that the main ground is connected to a clean and corrosion free bare metal surface. Also if there are is any dirt in the trailer connector you should clean it out.

Other than that you will just need to check to make sure the wires that run from the connector to the light assemblies aren't damaged.

I also attached an FAQ on troubleshooting 4-way installs for you to check out.

expert reply by: Jameson C