Connection of Black Wire on Hopkins Adapter 4 Pole to 7 Pole # 37185

Question:

I have a 2005 Ford expedition with the factory tow package and a 4 pin flat connector. I purchased the prodigy P2, wiring harness for my ford, and the 37185 adapter. I have installed the controller and it seems to be working fine. I have installed the the 37185 adapter, pluged it into my old 4-wire and hooked up the blue trailer break wire. Do I need to hook up the black 12 volt wire? Doesnt the trailer break voltage come through the blue wire? Can you please help my understand if I need the black wire and why.

asked by: Steve H

Expert Reply:

The Black wire is for a 12 volt power supply. If your trailer does not need a 12 volt power supply for electronic accessories, you will not need to run the Black wire.

You are correct, the power for the electric brakes comes through the Blue wire. Your brake controller should be installed using a Ford plug-in adapter # 3035-P that will connect underneath the dash of your Expedition.

The Purple wire is for reverse lights and can be taped up out of the way if your trailer does not have reverse lights.

The White wire is ground, and should be connected to a clean metal surface, preferably the vehicle frame.

I have linked an FAQ on brake controller installation for you.

expert reply by: Reno H