Troubleshooting 7-Way Install on Trailer and Brake Wont Work

Published 08/31/2015

Question:

I have a Ford F250 with the standard 7 pin socket. I am trying to figure out the wiring to hook it to my older gooseneck trailer. It is a Hillsboro with the 6 pin round plug. It does have brakes. I purchased a 6 foot extension with just bare wires on trailer side. I cannot seem to get it wired to match. I can get all lights to function but cannot get brakes to work correctly. Must have the brake wires in wrong terminals. Can you help? Thanks

asked by: Larry G

Expert Reply:

It definitely sounds like you have the brake output wire on your trailer not matched up with the wiring of your tow vehicle. Basically you will first need to determine which of the wires on your trailer wiring is for the brake output circuit. You can do this by tracing the wires from the 7-way to the brake assemblies, or you can try using a jumper wire from the positive post of a car battery to all of the wires of the trailer till you hear the brakes activate. You should hear a clicking type sound followed by a hum when they are activated.

I also attached a diagram that shows how 7-ways are normally wired.

expert reply by: Jameson C