How to Wire a Toyota Tundra with 4-Pole Connector to a Trailer with a 6-Pole Connector

Expert Reply:

It sounds to me like you have two running light wires on your trailer. The green and brown and yellow and brown wires are most likely right and left side running lights so both of these should most likely attach to the brown wire terminal which corresponds to the brown wire in the 4-Pole connector on your truck. This would mean that you only have 5 poles in the trailer connector that are used. These could be the left turn/brake, the right turn/brake, brown running lights, ground and electric brakes, power for the trailer or reverse lockout if the trailer has surge brakes. You do not have to use all six poles in the connector to make the wiring work properly, you just need to wire the functions to the correct circuits on the vehicle. Use a circuit tester, item # 3808 if needed to determine which wires power each function needed.

I would use the Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring, item # 37175, to wire the vehicle for the 4-Pole connector that you already have on the truck and a 6-Way connector that matches the trailer. You simply plug the 4-Pole connector into the connector on the back of the adapter and the lighting functions are complete from the vehicle side. You then need to wire the remaining circuits needed for the trailer functions. If the trailer has electric brakes then the blue wire will provide power from the brake controller to the center pin in the connector and the red wire is for auxiliary power to the trailer from the vehicle battery. You will need to use a 40 amp circuit breaker, item # PK54540 inline with the power wire to run this circuit to the vehicle battery.

expert reply by: Bob G