Troubleshooting No Brake Lights/Turns Signals on Trailer Wiring

Question:

Checked wiring on truck with multimeter and all plugs work correctly.

asked by: Patty

Expert Reply:

Sounds like you've eliminated the problem to being on the trailer side of your towing setup since all of the pins of your trailer connector are testing good.

Typically the issue with no brake lights/turn signals is related to an insufficient ground for either the trailer wiring as a whole or the main ground assembly of the wiring. Since both brake lights and turn signals aren't working I'd assume it's a weak ground for the trailer overall. To fix that you'd just need to make sure the ground wire of the connector is connected to a clean metal surface on the trailer frame. You can also run jumper wires from the ground wire back to the light assemblies as well.

I attached a couple help articles on trailer wiring for you to check out as well.

expert reply by: Jameson C