What Wiring Diagram do You Have for the Hopkins 7-Way # HM40975 on My Ford F-350?

Updated 11/16/2021 | Published 11/15/2021

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7- and 4-Pole Trailer Connector Socket w/ Mounting Bracket - Vehicle End

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Hook Probe Circuit Tester

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Question:

need a ford f 350 wiring diagram for hopkins 7 pin sae j1128. also how test vehicle 7 pin to match it to hopkins pin.

asked by: Jerry B

Expert Reply:

I can definitely help you out with that. On my end, I could not find a Hopkins 7-pin SAE J1128. With that being said, the most common 7-way on your F-350's end will look like the pins on the 7- and 4-Pole Trailer Connector Socket w/ Mounting Bracket - Vehicle End # HM40975. I went ahead and attached a diagram that shows the pin location and functions of each pin.

If you need a 7-way on your trailer's side, I recommend the 7-Way Molded Connector w/ 18' Cable - Trailer End # 50-67-106. It is important to note that the colors on this cable will not necessarily match the colors of the wiring on the vehicle's end. In order to match the functions on the trailer side, I recommend using the diagram and a tester to connect your trailer wiring. I went ahead and attached a diagram of the typical wiring colors on a trailer connection as well.

As far as testing the pins on your vehicle side, you will need to have someone sit in the truck and run through each function while you test the pins. For this procedure, you will need a circuit tester to make sure there is power running to each pin like the # PTW2993 to make sure there is power going to each pin.

expert reply by: Bob C