Purpose of Black ModuLite Box That Comes with T-One 118449 for a 2019 Toyota Highlander

Updated 06/25/2020 | Published 12/19/2018

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

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Question:

I want to install the Tekonsha wiring on my 2019 Toyota Highlander but I am a little confused. It looks like if I have the tow package I just need the one harness but since I don't have the tow package I need 2? What is the purpose of the second harness and that black box for the Tekonsha 118449?

asked by: Tony

Expert Reply:

The black ModuLite box that comes with the Tekonsha T-One # 118449 for your 2019 Toyota Highlander not only includes the connections needed to activate the trailer light wiring on your vehicle, but it also combines the light functions (like what almost every trailer uses), pulls 12V power directly from the battery so as to not strain your vehicle circuits, and provides protection in the case that your trailer wiring fails. To establish whether or not you have the tow package just look for the converter that is under your driver's side dash.

Both pieces install in the rear cargo area of your 2019 Highlander which you can see in the sample installation of this kit on a 2018 Highlander. If you would like to route the 4-Way connector to the hitch receiver then there should be a rubber grommet located under the tray in your rear cargo area. If you slice this open you can run the wiring through it and then mount the 4-Way with brackets # 18144 and # 18140. I also recommend sealing the grommet back up with Loctite RTV 598 High-Performance Silicone Gasket Maker # LT37467.

expert reply by: Jon G

Scott W.

6/22/2020

Great explanation! A couple follow-ups... 1) Do I have to run a dedicated power supply to the modulite, or can I tap into the power I'm already running for the trailer brake as part of the Tekonsha wiring. 2) Do you have a picture or description of what the tow package converter under the dash looks like? Thanks!

Chris R.

6/25/2020

The factory circuit that the modulite from the Tekonsha Harness # 118449 plugs into is already tied to the battery, so you won't need to manually run wiring to the Highlander's battery during installation. Unfortunately we don't have any pictures of the tow package module. If you're unsure whether or not you have the package the easiest thing you can do is simply call your local Toyota dealer with your VIN. They should be able to tell you right away whether or not your vehicle is equipped with the tow package.