Trailer Wiring for 2005 Chevrolet Silverado

Question:

my truck has 8 wires coming out the back . black 10 gauge wire , red 10, blue 10 , dark green 12gauge , lite green 12 , lite blue 12 , yellow 12 , brown 12 gauge wires . i would like to know how to wire this up to 7 terminal trailer plug . also i do not have a brake controller on pu . i know some trucks dont need controller to work trailer brakes . also i have winch on trailer i would like to keep trailer battery charged up on trailer . thanks

asked by: Ricky T

Helpful Expert Reply:

On the wires coming from the rear of your 2005 Chevrolet Silverado, there should be a white tag somewhere around the harness that will label the function for each of the 8 wires referenced in your question. If there is not one present, I recommend using a circuit tester like # PTW2993 to test each individually. Since you have 8 wires, one of them, most likely the light blue wire, should be just for license plate illumination or a similar lighted accessory. This wire will not be needed and can simply be tied off when connecting them to the trailer 7-Way.

While I still recommend testing the wires, the remaining wire functions on your vehicle are most likely as follows:

black - ground
red - 12 volt power
blue - electric trailer brakes
dark green - right turn/brake
light green - reverse lights
yellow - left turn/brake
brown - running lights

If you do not have an integrated trailer brake controller in your vehicle, I recommend looking at the Tekonsha Prodigy P2 # 90885 along with the custom plug-in harness # 3015-P. This is a great proportional controller that will activate your trailer brakes at the same time and with the same intensity that you apply to them in your vehicle.

I have also attached an article on wiring a trailer-mounted winch that you may find helpful.