How to Make Adapter to Go From 7-Way of Semi Truck to 4-Way

Updated 08/02/2017 | Published 08/01/2017

Products Featured in This Question

Roadmaster Brite-Lite 3-to-2 Tail Light Converter for Towed Vehicles

(119)

$57.87

Pollak HD, 7-Pole Round Pin Connector w/Cable Guard

(115)

$17.45

Wesbar 4-Pole Flat Connector w/ Jacketed Cable - Trailer End - 4' Long

(154)

$14.77

Question:

How can I go from a semi tractor plug to a 4 flat plug? I move different trucks, including semi tractors, around the country, and it would be great to be able to just plug into the outlet on the tractor and be able to plug in my 4 flat. Thanks for your help.

asked by: Dan M

Expert Reply:

The problem with semi truck 7-ways is that they have the turn signals separated from the stoplights so you end up with needing a converter installed on the adapter too so that the signal matches the trailer lighting.

If this is the case you can build an adapter using the part # RM-732 as a signal converter.

You will need a round pin male connector, # PK11702 and then the part # W787264 for a 4-way. Basically you will be splicing the converter between these two to create the adapter.

The 4-way comes with 4 feet of wiring that would not need all of so you could cut half of the wiring off it to use to wire up the 7-way to the converter.

I attached a picture of a diagram that has how a 7-way is typically wired.