Brake Controller Wiring Harness for a Tekonsha P2, # 90885, and a Ford 2004 Expedition

Question:

i have a 2004 expedition. I plan to buy a Prodigy 2 brake controller. What harness or part do I need to connect the truck to the brake controller

asked by: Mike I

Expert Reply:

The correct brake controller harness for a 2004 Ford Expedition and a Tekonsha P2, # 90885, is # 3035-P just as you have referenced. It will fit on models with a factory 7-Way or factory 4-Way. If you have a factory 4-Way, you will also need to add a 7-Way using # 37185.

The wiring to make the 7-Way fully functional should be in the plug that the 4-Way is connected to under the vehicle. There are more wires coming into the plug than coming out to the 4-Way so you would need to test the wires with a circuit tester like # PTW2993 to determine which wire has which function.

On the # 37185, the white wire has to be grounded to the vehicle frame. The black wire is 12-volt power. The blue wire is brake controller output to the trailer. The purple wire is for reverse lights.

expert reply by: Michael H