Adding 7-Way to Semi-Truck to Tow Fifth Wheel Trailer

Question:

5th wheel camper has 7 blade plug I have the normal tractor electric receiver round pins one large one for 30amp abs. Trying to figure how to integrate electric brake controller into setup and connect the two different electrical components?

asked by: Patrick

Expert Reply:

Semi truck connectors are typically wired differently than those on pickups that are used for recreational towing. The linked article on wiring includes diagrams that show the various configurations in use. In certain circumstances wiring adapters can help but we offer no 1-to-2 type adapter like what you describe. Also functions can be assigned to different wires on a semi and so some adapters may not work.

What you would want is the part # 37185. This will give you a 7-way that you could then wire to the semi truck's taillight wiring of the current connector. You might need a circuit tester like part # PTW2993 to determine the functions of the wires of the 7-way.

The 4-way of the # 37185 would need to get cut off. The white wire goes to ground. Green goes to right turn/stop, yellow to left turn and stop, brown to taillights, and then blue to the brake output of the brake controller.

expert reply by: Jameson C