How to Add Second Wiring Harness to 2018 Toyota Tundra to Power Tailgate Light Bar

Updated 01/03/2019 | Published 01/01/2019

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Hopkins Plug-In Simple Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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Question:

My 2018 tundra has a wiring harness. I’m need a additional plug for tailgate light bar. Will this plug into my exsisting wiring harnesses and be able to use and my factory plug ?

asked by: Jim E

Expert Reply:

If your 2018 Tundra has wiring that uses a round U.S. Car type connector (like the item shown in the linked photo) then you can easily piggyback a second wiring harness and have both remain active.

Most tailgate light bars use a 4-pole flat connector so if this is what you have all you need is part # 118384 which will simply plug in between your 7-way socket and the U.S. Car connector that connects to the back of it. Please check out the linked install video.

I strongly recommend using dielectric grease # 11755 on all connectors to block the entry of moisture and contaminants that can lead to connectivity issues in the long run. Just apply a small amount of the grease to the plugs before connection. It is also not a bad idea to use a zip tie or two like # DW05726-25 to both secure the connectors together (even though they do have locking tabs) and to safely dress any excess wiring to keep it out of harm's way.

expert reply by: Adam R