How To Install a 7-Way Trailer Connector and Brake Controller On a Freightliner Rollback M2

Published 11/03/2022

Products Featured in This Question

Hopkins Endurance Quick-Install 7-Way Trailer Connector with Universal Pigtail Harness - Vehicle End

(80)

$27.09

Deka Jacketed 2 Wire, 10 Gauge, Brake Wire - per Foot

(323)

$3.75

Wiring Kit for 2, 4, 6, and 8 Brake Electric Trailer Brake Controllers

(159)

$48.81

Question:

I have a 2020 Freightliner M2 rollback tow truck that is 34 feet long with only a 4 pin receiving socket at the rear. My PJ trailer is a 24ft tilt flatbed trailer with a 7 pin connector. How do I convert the 4 pin on my rollback to accept the 7 pin on the trailer? I am needing to know what to buy and have no idea. The trailer has electric brakes and what about a brake controller as well? I would imagine I would need one of those for inside the cab of the truck? Any help is greatly appreciated.

asked by: Zac

Helpful Expert Reply:

I do have an option for you but there aren't any direct wiring adapters to go from a 4-round to a 7-blade. Therefore, you'll need to remove the 4-round and install a 7-blade which is really your best option since this is far more common for trailers. In order to do this you'll need Hopkins Endurance Quick-Install 7-Way Trailer Connector part # HM47210. This will replace the 4-round and you can attach the wires from the 4-round to this(green, yellow, brown, white). It may not be color for color so you might need to test for function using a circuit tester. There are then going to be a few wires left over; red for power, purple for reverse, and blue for brake output. The purple can be capped but the red and blue will need to be run into the cab and engine bay with a wiring kit like the Wiring Kit for 2, 4, 6, and 8 Brake Electric Trailer Brake Controllers part # 5506. Please note, because of the longer length of the vehicle you'll also need extra wire, the Deka Jacketed 2 Wire part # 10-2-1 which is sold by the foot. Then, you just need to finish your connections for the trailer connector and make them for the brake controller, I recommend the Hopkins Agility Trailer Brake Controller part # HM47295.

I have attached a few help articles below that will assist a bit more with the installation.

expert reply by: Conner L