How to Determine Trailer Wiring Functions to Allow Installation of 6-Way Plug

Updated 07/10/2017 | Published 07/07/2017

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Trailer Wiring Junction Box

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$35.53

Ring Terminal - 12-10 Gauge Wire - 3/16" Ring ID

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$1.17

Question:

I have an Escapade trailer and has six wires coming from the trailer wiring harness the colors are black green red white and yellow and it looks like purple Im trying to figure out how to connect this to a 6-pin connector with the colors on the 6 pin connector being white purple red blue green and yellow Ive tried different ways to write up but nothing seems to work can you help

asked by: Doug P

Helpful Expert Reply:

I can help you with your trailer wiring.

The first thing to do is to confirm the function carried on each of the trailer's wires/circuits. This is easy enough to do with a spare 12V battery (or the one in your vehicle). What you want to do is connect 12V power to each wire, one at a time. Typically white wires are ground so connect the white wire to the battery negative post. You may be able to rtace the wires and find the one that attaches to the trailer frame as ground. Then connect each of the other wires to the positive post, one at a time, and see what happens on the trailer. For example, one wire may activate the trailer's right or left stop/turn lights. Another may activate the electric brakes (if the trailer has them).

There are common wire colors used for particular trailer functions, such as a blue wire to carry brake signals, but there is never any guarantee that any given trailer uses the common wire colors.
You can refer to the linked article on trailer wiring to see each of the type of connector formats, 4-pole, 5-pole, 6-way and 7-way, and what signal each pin on each connector type carries. The moral of the story is wire by function, not by color. Once you know the trailer wire functions it will be a simple matter to connect a trailer 6-way plug like # 50-61-104 or # 50-61-108 based on the diagram in the article.

It is probably easiest to make those connections using a junction box like # 38656 along with ring terminals like # 44-5310A. Ring terminals on both the trailer and 6-way plug's wires will make better connections and also make it a lot easier to replace the plug if it should ever develop corrosion or be damaged by road debris.

expert reply by: Adam R