Industry Standard Wiring Configuration for the 4-way Round Trailer Connector

Published 02/04/2009

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Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Connector - Chrome - Trailer End

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Hook Probe Circuit Tester

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Question:

Do you have the correct wiring diagram for the round 4 wire connector.

asked by: Tom

Expert Reply:

Most of the time the 4-Way connector is wired as follows. Looking at the front of the socket on the vehicle side with the cover raised the top left pole is the yellow, left turn/brake pole, the top right pole is the right turn/brake pole, the bottom left pole is the white ground pole, and the bottom right pole is the taillight pole. The trailer side, part # PK11409, will be a mirror image of the vehicle side.

Unfortunately, there is not an industry standard wiring configuration for the 4-way Round Trailer Connector, part # PK11409. You will need to use a circuit tester, part # PTW2993, and find out which pins presently transmit which functions. In general, on a trailer, the white wire is the ground wire, the yellow wire transmits the left turn/brake signal, the green wire transmits the right turn/brake signal, and the brown wire is the running lights.

expert reply by: Andi