How Do I Determine Which Functions Are Which On Trailer Wiring

Question:

Dont know what colors to match from trailer side to 7 way connector side

asked by: Dan B

Expert Reply:

The only true way to determine the function of a wire or pin on a 7 way plug is to test it using a circuit tester like the Cordless Circuit Tester # PTW2979; unfortunately colors are not standard or a reliable way to determine function.

If you're going to be adding a new 7 way connector like the 7-Way Molded Trailer End # 54006-009 to your trailer, you'll want to connect each wire to a battery and ground to determine which function is activated when power is supplied. Once you're determined what the existing wires on the trailer, you can wire in the new 7 way connector on to your trailer.

I've also linked a diagram, an installation video of a 7 way RV connector and one of our helpful articles on 7 way trailer wires that will show you how 7 way connectors are typically wired.

expert reply by: Erik B