I have a 2005 Ford F250 SD with power stroke and tow Pkg., I went to install Tekonsha Primus and discovered previous owner cut out OEM trailer harness. Which color of wires do I hook up the brake control box to now? Should I tap into the wires coming off the brake pedal?
Expert Reply:
At this point, the easiest thing to do would be to install the brake controller as if the vehicle was not wired. The four leads coming off the brake controller are wired as follows:
The red wire would tap into the wire coming off the cold side of the brake switch located above the brake pedal. The easiest way to locate this wire is to use a circuit tester, like part # 40376, and locate the wire that only shows current when the brake pedal is pressed.
The black wire would run to a 12 v power source, usually to the underhood fuse box.
The white wire is grounded, and the blue wire is the brake output, and would run back to the 7 way connector on the vehicle bumper.
I attached a link to a page on wiring a brake controller from scratch that you might find informative.
expert reply by: Mike
