Does Trailer Get Ground For Lights From Hitch Ball On Vehicle?

Updated 03/31/2021 | Published 03/29/2021

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Optronics Trailer Tail Light - Stop, Turn, Tail - Round - Grey Flange - Red Lens

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Hook Probe Circuit Tester

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Question:

I recently pulled the back of my car up to my new home-built trailer and connected the 4-way connectors to test the functionality of the lights. They did not illuminate. After reading about proper grounding, Im wondering does the trailer tongue need to be resting on the ball for a proper ground to be made?

asked by: Jeffrey M

Helpful Expert Reply:

You do not need to have the trailer hitched to your vehicle as the ground for the trailer is actually one of the pins of the 4-way connector.

Since the new lights are not functioning I recommend double checking that all of the wiring connections made are secure and one did not come loose and that the main ground to the trailer tongue is secure. If your trailer has an aluminum frame or a tilting bed you will want to run all of the ground wires from the lights to the main ground on the tongue.

Second some lights have a ground wire, and some ground through the mounting hardware. If your lights do not have a ground wire you will want to make sure that the lights are mounted to metal that is corrosion free.

If all of the grounds look good, I recommend double checking that you have power from the 4-way connector on your car making it to the lights. You can do this by using a circuit tester like # PTW2993.

If you are not getting power you will need to trace the wiring from the lights to the connector and make sure that the connections are correct.

I included a link to a helpful article on trailer wiring for you to take a look at.

expert reply by: Samuel C