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 # 3808 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