Wiring in a Trailer Brake Controller to a Factory Wiring Harness on a 2012 Toyota Tundra

Question:

Journey HD 52740. four wire out the back. white-grd. black-batt. blue-brake. red has STL ? My factory harness has two wires left after I hook battery. brake. and ground. a green wire and a green-white wire. where do they hook to ?

asked by: Bill

Expert Reply:

The green with white wire is the one I show as connecting to the red wire on the controller. But if you want to be certain, you can test the wires on the factory harness using a circuit tester like # PTW2979 if you need one. One of the remaining wires will attach to the red wire on the controller. This is the input circuit from the brake switch. It tells the controller when you are stepping on the brake pedal.

To find which wire is correct, step on the brake pedal while testing the wires with the circuit tester. The wire that shows power ONLY when you step on the brake connects to the red brake control wire. If you find the wire but it also shows power when the headlights or turn signals are on it is not the correct wire.

The other wire will not be used. Generally this is an illumination wire but the brake controller does not use it. Tape it up and stow it out of the way.

expert reply by: Michael H