Will the 4 Pole to 6 Pole to 4 Pole Trailer Wiring Adapter Work For My Trailer

Question:

I have a 4 flat connector on the vehicle and a 6 round on the trailer. There are no electric brakes on the trailer. There are 6 wires in the existing 6 round. White, black, green, yellow, brown and red. I thought that I had everything figured out, but the red wire confuses me. I have part # 37175 on order which I thought would work to connect the two. Do I have a separate brake wire red? And if so, where does it connect and will the 37175 work for me? I get it that the white is neutral, black hot, green and yellow turning and brown running lights. But the red?

asked by: Jay

Expert Reply:

The Hopkins 4 Pole to 6 Pole Trailer Wiring Adapter # 37175 will work to connect your vehicle wiring to your trailer wiring. However, you will need the Wiring Kit for Brake Controllers # 5506 to make the adapter fully functional. The 6-way adapter has three wire leads: the blue is for electric brakes, the red wire is the hot lead and the white wire is the ground wire. I attached installation videos of the wiring adapter and wiring kit you may want to check out.

There are two standard wiring pin outs for 6-ways which can be seen in the diagram I attached. The function of the center pin and 2 o'clock pin on the trailer side can be switched on some trailers. This means on the 6-way wire adapter you are looking at, the blue wire for the electric brakes and the red hot wire may need to be switched depending on how the trailer is pinned. It is possible you may need to swap the blue and red wires on your adapter. Assuming your trailer is wired correctly with no issues, the adapter and wiring kit will work with your trailer.

Keep in mind, there is no standard for trailer wiring colors. If you are wanting to know what exactly the red wire does, you can follow the wire on your trailer as far as you can until it terminates or you can test it using a 12v battery and see what happens. At some point the red wire could of have been connected to brakes. A past owner may have disconnected the wire and capped off the end, or the trailer manufacturer may have decided to not have brakes on the trailer. Without being able to physically inspect the trailer, it would be hard to confidently determine the function of the red wire without troubleshooting.

I have attached our wiring help article you may want to look at.

expert reply by: Sarah H