7-Way Trailer Connector and Brake Controller Installation on 2003 Ford F150

Question:

I want to convert from a 4 pin to 7 pin trailer adapter on my 2003 f-150 stepside. Im unsure of which adapter I need for the brake controller because I have two connections under the dash and one looks like it would be where a brake controller goes. I also am unsure of what relays I would need to install in the fuse box to complete the project. FYI I will probably install your Tekonsha Prodigy P2 Trailer Brake Controller - 1 to 4 Axles - Proportional

asked by: Lyle S

Expert Reply:

To install a 7-way on your F150, use the Tow Ready # 118242 wiring harness. To plug in the harness, you'd simply trace the wiring from your factory 4-pole back to where it plugs in on the frame rail. Separate that connection and plug the # 118242 inline. Ground the white wire with the ring terminal to the trailer frame and install the fuses and relays per the instructions.

The connector that the # 3035-P plugs into would be located under the dash, usually near the diagnostic port. The connector would be a gray 6-pin plug. To determine if you've got the correct plug, you can use a circuit tester like part # PTW2993 on its pins. One pin should show a constant 12-volts, while there should be another pin that only shows voltage when the brake pedal is pressed.

I've linked you to an install video you might find helpful.