7-Way Trailer Wiring Configuration

Question:

7 wire trailer harness connector, no reverse used. 6 wires on the harness, no black wire. How do I hook them up for everything to work?

asked by: Joey

Expert Reply:

If either your vehicle or trailer 7-way wiring does not have all wires connected to activate all of the 6 possible circuits you can make that last connection to activate it.

On the trailer side it is really easy to install a new full-functioning 7-way plug by adding a junction box like # HS381-9000. This junction box includes a pre-wired 7-way trailer plug, like the one shown in the linked photo which is wired to the RV standard.

By installing this box on the trailer you get a handy protected place for making the needed wiring connections from the existing trailer wiring. You'll need ring terminals # 44-5310A for each trailer wire you need to connect within the box.

To help you keep the wiring straight I linked an article that covers everything on trailer wiring. This shows you which pins carry which functions and will help make it easy to get everything working. In a case where the reverse lights are not used/needed that circuit on the trailer side could certainly be assigned to a differenet function if you wish.

expert reply by: Adam R