Necessity of Routing Power Wire for T-One Wiring Harness # 118422 When Installed on 2010 Ford Fusion

Updated 06/07/2012 | Published 06/05/2012

Question:

Is it required to hot wire to the battery to install wiring for my tow hitch? Id prefer a harness w/ a simple plug- in in the rear.

asked by: Wayne

Expert Reply:

Although the T-One Vehicle Wiring Harness you mention obtains its signals from plugging inline with the existing tail light wiring harnesses, the voltage to power the trailer lights needs to be drawn directly from the battery. The reason for this is twofold. First, the vehicle manufacturer has determined that any voltage drawn through the vehicle wiring over and above that needed to operate the vehicle tail light assemblies could overload the vehicle wiring system and damage it. Secondly, drawing the power directly from the battery will isolate the vehicle wiring from that of the trailer and protect the vehicle wiring should a short circuit occur.

A wiring harness that would simply plug into the tail light assemblies without needing to draw power from the battery is not available.

The process of running the wire from the rear of the vehicle to the battery is not too difficult. I have linked you to the installation instructions for the harness, as well as an install video that you might find helpful. I will also link you to an FAQ article that will provide tips on how to run that wire.

expert reply by: Mike L