How to Wire a Replacement 6-Way Trailer Connector Onto Old Cattle Trailer

Updated 03/05/2012 | Published 02/29/2012

Question:

I have a 1988 cattle trailer made by Kaufman Trailer co. and the old plug wore out and I bought a new one from the local hardware store. It is a 6 pin and the truck is a 95 model ford f250. So the problem is: the plug on the truck is old and has a different layout than the plug i just bought. What color wire is which function. I can figure it from there but the color code you have at the top of the page is different than how the trailer itself is wired. And no one has rewired the trailer so it is just how it came from the manufacturer.

asked by: Cody G

Expert Reply:

Typically, the connector wires as follows:

Brown wire: tail lights
Green wire: right turn and brake
Yellow wire: left turn and brake
Red wire: brake output voltage
Black wire: auxiliary

If this does not match up with the way your trailer is wired, you will have to wire it by function, not wire color.

The best way to do this would be to use a car battery and apply power to each circuit on the trailer wiring harness. Ground the negative battery terminal to the trailer frame, and apply voltage to each circuit to determine its function. Once the function is determined, attach the wire to the correct terminal on the trailer connector. The terminals on the trailer connector are typically labeled, T for tail light, R for right turn and brake, L for left turn and brake, S for brakes, G for ground and A for auxiliary.

expert reply by: Mike L