Pilot Brake Controller Wiring Issue on a 2003 Ford F-350

Question:

I am trying to hard wire a Pilot Trailer Brake Control into my 2003 Ford F350. There are the four wires on the brake control...problem is I do not have a black wire in the cab of my truck. I have a small gauge brown, green, white, red and blue...I cannot find the black wire anywhere.

asked by: G

Expert Reply:

It sounds like a wiring harness may have been installed at some point for a brake controller. Your 2003 Ford F-350 should have a gray OEM plug under the dash near the diagnostic port for a plug-in style harness like part # 3035-P. The wire colors that you mention are not typical colors for brake controller wiring. I have attached a help article on installing a brake controller on your truck for you to check out.

I recommend looking under the dash for the OEM brake controller plug. If the wires you found are attached to that plug, you can use the Tekonsha Plug-In Harness # 3035-P, cut off the flat 4-pin black connector and splice in the wires from your brake controller color for color.

If you cannot find the OEM plug, then the only way to determine the function of each wire is to test the wires using a circuit tester like part # PTW2993. Since they are not all standard colors, I would not try to wire color for color. You should have one wire that only has power when the brake pedal is pressed, the truck may need to be on for this wire to have power. That wire will connect to the red wire from the Pilot. You should have another wire with constant 12 volt power. This will connect to the black wire from the Pilot to power the brake controller. The white wire from the Pilot should be grounded and the blue wire should be connected to the trailer connector at the back of the truck. On Ford trucks, this is typically a blue wire.

expert reply by: John H