Replacing 6-Way on Truck with 7-Way

Published 04/19/2017

Question:

I have a 1970 c10 pickup, it has a 6 round already wired in. Would it be pretty simple to replace that with a 7 blade?

asked by: Phil

Expert Reply:

Since wire color codes are NOT universal, we always recommend wiring by function, rather than wire color.

If you look at the Trailer Wiring FAQ article I have linked you to, you can see some diagrams showing the proper way to wire a vehicle and trailer side 7-way trailer connector.

If you can open up the existing 6-way connector on your trailer, take the housing apart and look at the terminals the wires attach to. In many cases, they will be labeled like what is shown in the FAQ article. You can then label each wire, so they are connected to the proper terminal when you install the 7-way. If the terminals are not labeled, you can physically trace each circuit, or you can use a 12 volt battery, attach the trailer ground to the negative post and apply power to each circuit to see which function powers up.

For a 7-way socket with wiring we have the part # HM40975-11998.

expert reply by: Jameson C