Wiring an Old Trailer with a New 7-Way Connector and Figuring out the Wires  

Question:

Expert Reply:

I would start by getting a RV-Style Trailer Connector, item # PK12706, to wire your trailer. You will need this connector since your trailer has reverse lights. If your trailer has brakes you will also need a brake controller and wiring to install it in your vehicle.

I would connect a wire to the tail light circuit in the 7-Way connector and check each one of the wires on the trailer independently, labeling them as you go. You will also need to make sure a there is a ground wire from the connector to the trailer frame. We have wiring diagrams on our wiring page (see link) for you to see where to connect the wires needed to test the trailer lights. Once you have the ground connected and the wire ran to the tail light circuit in the connector turn the tail lights on and use this wire to check each wire on the trailer, being careful not to short the wire to the trailer frame. The turn signal and brake wires are on the same wire so the brighter element in the tail light will be the turn/stop circuits and the dimmer element will be the tail lights. You most likely have more than one wire that needs to be connected to the tail light circuit since you have clearance lights so the wires that activate the clearance lights will also need to be connected to the tail light circuit. To check the brake wires you will most likely be able to hear the magnets engage when power is applied to that wire, or you can lift a wheel with brake drum and try to turn the wheel when power is applied to the wire. The power wire will run any internal lighting or provide charge maintenance for a trailer mounted battery.

In the 7-Way connector the reverse light circuit is connected to the center pole. Then inside the trailer connector with the retention tab up the 1 O-clock connection is for 12 volt accessory power, the 3 O-clock connection is the right turn/brake connection, the 5 O-clock connection is the brake output, the 7 O-clock position is the ground wire, the 9 O-clock position is the left turn and brake, and the 11 O-clock connection is for the tail lights.

expert reply by: Robert G

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