Troubleshooting Electric Brakes That Do Not Work

Question:

I just bought a new Ford F-150 with the towing package. I had to put a new 7 way plug on my trailer end. Got everything wired up but my trailer brakes. I have a separate, 12 gauge, 2 wires going form the plug to the brakes on the left hand side. They then splice in at that side of the axle and go over to the right side brakes. When I wired it up to the plug I hooked the black wire to the electric trailer brake screw and the white wire to the left side brakes. My truck says this is wrong. How do I correct this to have brakes? I have the factory brake controller in the dash. Where should the wires go? Thanks so much for your help as we have trailer companies within 75 - 80 miles of my area. So I really have no where to go to ask questions.

asked by: Michael B

Helpful Expert Reply:

It sounds like you may not have wired everything like it should be, particularly the ground wires. Each brake assembly is going to need to have a pair of wires coming out of it, with both having ground wires that are attached to bare metal surfaces on your trailer frame.

Then run a power wire to your trailer brakes and connect it to the wire which was not grounded (on either of the brakes) and run another wire from the power wire on that brake to the brake on the other side of the axle. It sounds like this is something you have already done, which is why it seems like your issue is with the ground wiring.

I've added a link to an article on parts needed to add electric drum brakes which talks about how to wire your brakes which you may find useful.

expert reply by: Kyle S

George S.

6/21/2020

How is the best way to connect the electric brakes to the tow vehicle.The electric brake has 2 green wires coming out. How do I find the hot wire and which is the ground wire

Chris R.

6/24/2020

Each electric brake assembly does have two wires - one for ground and one for power - the good news is that it doesn't matter which wire you choose for each function. Simply attach one to the frame for ground and run the other to the brake output wire coming in from the trailer's 7-Way.