7-way Trailer Connector Color Codes For Wiring In a 4-Pole Connector

Updated 09/06/2019 | Published 09/05/2019

Question:

How do I wire a 7 way trailer to 4 way car connector? what are the cross color codes between the two? when I wire yellow to yellow, green to green, brown to brown, and white to white, I get no running lights and both tail lights flashing for both left turn and right turn.

asked by: Greg G

Expert Reply:

There's more than one accepted wire color code convention for a 7-way trailer connector. Many times, a 4-pin connector would wire in color for color, but not always. On some 7-ways, the red wire will be left turn/brake lamp instead of the yellow wire. The brown wire will be right turn/brake lamp instead of the green wire. The green wire will be the taillights and the white, blue and black will be the same.

It's usually better to wire by function than by wire color, because wire colors aren't always consistent. I'll link you to a help article that shows the pinout and the function of each pin.

If your existing 7-way connects to the round tow package connector (called a US car connector) the easy way to do this would be to use a combination 7-way/4 pin connector like # HM40975.

expert reply by: Mike L