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Why Does Trailer's Wiring have Two Brown Wires  


The wires from the trailer are yellow, green, and two brown. The green and yellow ones are paired with a brown wire. The harness has green, yellow, brown, and white. Do you know how I can match these up?


Expert Reply:

The brown (running light) wires all run to each other as they carry the same circuit. The reason there is two browns on the trailer side is because there are running lights that are on both sides of the trailer.

Aside from that all the rest of the colors match with the white running to the trailer frame as a ground.

expert reply by:
Jameson C
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Joel P.


I don’t think you answered his question. He’s asking about trailers that havent spliced the two brown wires into one wire. He’s asking how does he match up these two wires coming out of the trailer harness to one receptacle at the trailer hook up on his truck. I.e. does he have to splice and solder the wire or is there another way to connect the 2 to 1 plug. I have a similar trailer with two brown wires one yellow one green and the ground white.

Etrailer Expert

Jon G.


Soldering the wires together and protecting them with a heat shrink like part # DW05452 (slid over the wires previous to soldering) is the best way to make your wire connections. Not everyone is comfortable with this method though so in that case you can use butt connectors # DW05744-5 and put both brown wires that run down the sides of your trailer for the running lights in one end while you have the other brown wire that goes to the trailer connector in the other end. If you have a 7-Way on your trailer then using a junction box like # 3430001-JBK makes this a lot easier.

Joel P.


Thanks-I soldered like you described and it worked well.

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