How to Determine the Factory Trailer Wire Functions on a 2005 Ford F-150

Updated 11/18/2013 | Published 11/15/2013

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Question:

I have a 2005 f150 and i was wondering what the color code was on the 5 wires coming off the harness. I bought a Hopkins 7 blade wiring kit because the other one got ripped off and I dont know which wires to put where.

asked by: Jonathan

Expert Reply:

I may have some information that will help, however, vehicle manufacturers are notorious for changing the wire colors on their factory trailer wiring, so the best way to determine the function of each wire is by testing. To test the wires, I recommend using a circuit tester like part # PTW2993. Find a good ground for the tester and test each wire as a helper activates each light function on the truck.

We had a 2006 Ford F-150 on our lot with the factory tow package wiring, so I went to take a look at the wiring. On this truck, Ford used the following colors for each function:

White wire - Ground
Blue wire - Electric Brakes
Yellow wire - Left Turn/Brake Lights
Green wire - Right Turn/Brake Lights
Orange wire - 12-volt power
Grey wire w/ white stripe - Tail Lights
Pink wire w/ black stripe - Reverse Lights

Ford has also been known to use the following wire colors.

Orange wire w/ Blue stripe - Right Turn/Brake Lights
Light Green wire w/ Orange stripe - Left Turn/Brake Lights
Brown wire - Tail lights
Black or Grey wire - Ground
Black wire w/ Pink stripe - Reverse Lights
Blue wire - Electric Brakes
Red wire - 12-volt power

Again, I strongly recommend testing each of the wires for the proper function before making any connections to prevent possible shorts, blown fuses or light failures on the vehicle and trailer.