Adding a 7-Way Trailer Connector to a 28 Foot Trailer with Electric Brakes

Question:

Will this harness work for a 28 foot tandem axel brakes on both axles flatbed trailer or do I also need to buy the brake wire by the foot and connect everything in a junction box? this trailer also has 4 marker lights on each side.. Thanks

asked by: Sara

Expert Reply:

The 5th function for 40 ft. Wishbone 5-Way Trailer Harness with 30" Ground and 5 ft. Blue Wire Item # A40W5B is meant to go into an electric reverse lockout on a trailer with surge brakes. On the vehicle side the 5th function ties into the reverse lights so that when the vehicle is in reverse the lockout solenoid will be energized and not allow brake fluid to actuate the brakes.

Usually on a trailer with electric brakes both the trailer and the vehicle will have a 7-Way trailer connector. You can add one with a junction box to the trailer using # HS381-9000. Then you could use wire # DW04914-1 to go from the junction box to the lights and brakes. This wiring is sold by the foot.
50-67-103 which is 15 feet long so you probably will need additional wire.

In order to then operate the electric brakes the tow vehicle will need to have a 7-Way connector and a brake controller. I would need to know the year, make, and model of the tow vehicle as well as the type of trailer connector it has now, if any, to make specific recommendations.

expert reply by: Michael H