Converting A 5 Wire 4 Way Trailer Connector To Vehicle 4 Way Flat

Updated 08/06/2021 | Published 08/04/2021

Products Featured in This Question

Hopkins Wiring Harness with 4-Pole Flat Trailer Connector - Trailer End - 4' Long

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$6.58

LCD Digital Circuit Tester

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$26.67

Question:

Hello I have a boat trailer with green / brown coming off one side and yellow / brown coming off the other side, also a ground white wire.. How do I hook them up to the 4 flat plug

asked by: Nick

Expert Reply:

It sounds like you have a separated wiring setup with 5 wires - yellow, yellow brown, green, green brown, white. Typically, yellow is left turn / stop, green is right turn / stop, yellow brown is left running light, green brown is right running light, white is ground. You convert this to a standard 4 way by wiring the 5 wires to 4 flat harness # HM38138. This allows you to wire up all of your trailer wires color for color and then simply plug it into the vehicle's 4 way connector.

The following layout is typically how you would make the conversion:

White Wire = White Wire for ground connection.
Green/Brown goes to 4 way Brown
Yellow/Brown goes to 4 way Brown
Yellow goes to 4 way Yellow
Green goes to 4 way Green

Keep in mind, color is almost always a good way to determine the function of each wire, but the only way to truly know is by using a tester such as LCD Digital Circuit Tester # PTW2992. I attached demonstration videos for you along with a wiring diagram.