Where is the Blue Electric Brake Wire on a 2000 Ford E-350 Van with Brake Controller Port

Question:

I have a 2000 Ford E-350 Van 15 pass. I purchased the factory wiring harness for the brake controller. It plugs in under the dash just fine. The proble is I cant find the Blue#10 wire under the vehicle. The van is wired from the factory with a 4-way flat but there is No additional wires in this harness. Where does the Blue wire terminate.

asked by: mark s

Expert Reply:

This is a good question as Ford has terminated the wire in various places over the years. So, I can tell you some likely places, but you will need to do some testing using a circuit tester, like # PTW2993, to find the right wire.

In order to find the correct blue wire, you can look under the hood, on the driver's side, near the firewall, behind the power distribution box. You might have to remove some components, like a plastic reservoir (see video linked below) in order to reach this nest of wires. You will need to run power through the blue wire at the port where the brake controller plugs in, in order to locate the wire elsewhere on the vehicle. Using the circuit tester, start probing blue wires until you find the one that carries the 12-volt signal you are supplying via the port. Tap into this wire using a quick splice and attach a length of wire to it, run it back to the rear of the vehicle, and finally connect it to a 7-Ways blue wire.

Another method is to try to trace the wire back from the port. It will be going through the fire wall somewhere on the drivers side. You could also tap into the back of the port where the blue wire is and route a wire from there, through the fire wall, and to the rear of the vehicle and 7-Way.

I have included a video that might help. Your blue wire might be located elsewhere but they go over the procedure they used to find it.

expert reply by: Michael H