Installing a 7-Way Trailer Connector on a Trailer with 6 Wires

Updated 03/14/2014 | Published 03/13/2014

Products Featured in This Question

Pollak 6-Pole, Round Pin, Trailer Wiring Connector - Trailer End

(172)

$7.80

Trailer Wiring Junction Box

(816)

$27.58

Hopkins 7-Way RV Style Connector with Molded Cable - Trailer End - 8' Long - RV Standard

(908)

$46.90

Question:

My trailer has black, blue, red, green, yellow and brown wires. My 2003 Chev K2500 has the 7 blade plug receiver. Can I wire a 7 blade plug on my trailer and have running lights, electric brakes, brake lights and turn signals? I do have a brake controller.

asked by: William

Expert Reply:

You can certainly add a 7-way trailer connector to your trailer with 6 wires. You would simply have 1 pin on the 7-way connector that did not function. I recommend adding a 7-way molded trailer wire connector like part # H20046, and a junction box like part # 38656. We do this on all of our trailers and our customers trailers and it will make future wire maintenance much easier. I have attached an installation video of these two parts for you to check out.

Once you have all of your parts, you will want to determine the functions of each of the wires on your trailer. If you do not already know the functions of each wire, I recommend using an independent 12 volt power source (I use a vehicle battery) to apply power to each wire to see what happens. For example, if you apply power to the green wire on your trailer and your right brake light/turn signal comes on, then you know the green wire is for the right brake light and turn signal.

At the junction box, you will want to match the wires from your trailer to the wires from the 7-way harness by function, not by color. Trailer manufacturers do not stick to a standard wire color code, so it is very important to verify the function of each wire. If you choose to go with the molded harness that I recommended above, the functions of each wire are listed below.

White Wire - Ground
Red Wire - Left Turn and Brake Lights
Brown Wire - Right Turn and Brake Lights
Green Wire - Tail Lights
Blue Wire - Brake Power
Black Wire - 12 Volt Power
Yellow Wire - Auxiliary Power/Reverse Lights (This wire may not match up with the wires on your trailer)