How to Install 4 to 7-Way Adapter # 37185 on a 2001 Ford F-150 and Utilize Electric Trailer Brakes

Expert Reply:

The # 37185 adapter would be a good choice to convert your 4-pole plug to a 7-way plug.

To install the # 37185 adapter, you would first plug the matching connector, and then connect the additional wires. If you view the image of the adapter, you will see a white ground wire, as well as three additional wires colored blue, black, and purple.

You will connect the additional wires as follows:

White: Ground, attached to a suitable location on the vehicle frame.
Black: Run to the vehicle positive battery terminal, with a 40amp circuit breaker like part # 9510.
Blue: Connected to the blue electric brake wire coming from the brake controller in the vehicle cab.
Purple: This is an auxiliary wire, and can be used as a 12v power source, or to power a reverse light function if needed. If not, this wire can be tied up.

You will need to install a brake controller to power the electric brakes on your trailer. I recommend the Tekonsha P2 brake controller and wiring adapter kit # 90885-3035P.

Using the brake controller and wiring adapter kit, the controller will be able to plugged into the connector under your vehicle dash, in line with the brake pedal.

If you prefer not to hardwire to equip your vehicle with a 7-way, there is a plug-in 7-way connector available for your 2001 Ford F-150. Replacement OEM wiring harness # 118242 would allow you to easily install a 7-way plug while retaining the use of your OEM 4-way plug.

I have included the installation instructions for the 118242 wiring harness.

expert reply by: Sarah L