Trailer Connector is a 4-Way Flat but has 5 Wires

Question:

Attempting to replace my connector for my trailer lights. connector from car, wires are: white, brown, yellow green. Connector wires from trailer: yellow/black 2 wires, green/black 2 wires, and a brown, which is the ground wire. How do I match them up with the new connector.

asked by: Vince

Expert Reply:

On the vehicle side connector, white is ground, brown is running lights, yellow is left turn/brake lights and green is right turn/brake lights.

On the trailer side, since the black is the ground we can move on to the other wires. You likely have 2 running light wires, one for each side of the trailer. This is done so you don't have to splice in a jumper wire from one side of the trailer to the other. So the yellow wire is likely the left turn and brake light, green is likely right turn and brake light. And the other 2 wires are running lights.

You can either trace the wires back to see where they terminate to determine function or you can apply 12 volt power to each one to see what lights up to determine function.

expert reply by: Michael H