How Does 4-Way Wishbone Trailer Wiring Work and Install

Updated 06/13/2012 | Published 06/09/2012

Products Featured in This Question

Pollak Black Plastic, 7-Pole, RV-Style Trailer Connector - Trailer End

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$6.44

20 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 30" Ground

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$16.85

Question:

I bought a new 4 pole light kit for my car trailer and it was a V style where you run wires down both sides of trailer and I didnt like the way wires routed so I ran them down 1 sideright side Problem is I cant get my side running lights to work, I connected them to left side tail wiring and routed 1 wire over to left side, should I have connected it to right side wiring then run it over to left side does it know difference?.Also the wires are yellow/brown and green/brown so I have 2 browns, do I hook 2 browns together on one lug on trailer connector.Do they need to be grounded also as they did not have ground wires on them Hopefully you follow what Im saying haha, 2009 chevy 2500 HD diesel

asked by: Scott F

Expert Reply:

You have what is called a wishbone harness like # A20WB. This type of harness take the running light circuit and splits it at the trailer connector so that you do not have to run a jumper wire from one tail light to the other. The yellow/brown wire is the running light circuit for the driver side. The green/brown wire is the running light circuit for the passenger side.

Either of these wires will carry the running lights for the trailer, they are just split to make it easier to wire to the tail lights.

Many trailer lights ground through the mounting hardware if there is not a ground wire present. All lights will need to be grounded. If you have a lot of extra running lights, they may be too much of a power draw for the vehicle wiring system to handle and thus they will not power on.

All grounds, including the main trailer connector ground, will need to be attached to clean and corrosion free bare metal surfaces. On aluminum trailers, if the ground to the frame at the lights is not sufficient, they will not work and you will need to attach those grounds to the main trailer connector ground.

expert reply by: Michael H