bing tracking image

Tekonsha T-One Vehicle Wiring Harness Installation - 2019 Toyota Highlander

content loading

Products Featured in this Video

How to Install the Tekonsha T-One Vehicle Wiring Harness on a 2019 Toyota Highlander

Today on our 2019 Toyota Highlander, you're going to be taking a look at, I'm going to show you how to install the Tekonsha T-One vehicle wiring harness with four pole flat trailer connector.This is what our wiring looks like when it's installed. This is going to give us all the proper lighting functions to safely tow our trailer. Both turn signals, our running lights, and our brake lights. It's going to come with a converter box to protect our factory wiring from any backfeed from our trailer if our trailer has a wiring issue. This setup is for a vehicle that does not have a factory tow package. We're also going to have a nice dust cap to help protect our connections from any dirt and debris.When you're ready to use it, you simply lay it overtop the rubber seal, close your hatch, hook up to your trailer, and you're ready to go.

When not in use, you simply roll it up, store it in your inside compartment, and it stays out of the way.First thing we need to do, we need to remove all of our floor coverings on the inside rear of our vehicle. We're going to have a few tie downs here that have fasteners in them, we're going to need to remove those. Remove everything down here on the bottom. Taking your trim panel tool, you're going to have some little push pin fasteners that run across the back of your carpet here. We're going to pull those off, just like this.

We'll go ahead and pull these out so you don't lose them, then we'll fold that up just like that.Grab a panel right over here on the side, we're just going to pop it up. It's easier if you have a trim panel tool, you just get under one side there like that, and then we'll set that aside. We're going to have a ten millimeter head nut right here. Keep in mind, this is on our driver's side. Then we're just going to pop out our center section.

We'll go ahead and take it out and set it aside.Next we're going to install our converter box. I'll go ahead and install my fuse. Then I'm just going to zip tie my wiring harness, or my converter box, right here to my existing wiring. Your kit does come with some two-sided sticky tape if you wanted to stick it on there. Sometimes sticky tape doesn't always stay stuck on there, it'll come off, and then you have this rattling around.

If you do that, I would suggest going ahead and putting zip ties on there anyway. I'm just going to use zip ties.Then we'll install our four pole plug. Go ahead and wrap it across, just like this. Go ahead and throw a zip tie on it to hold it in place, and then we can reinstall our panels. Now, when running your four pole wire, once you've put your panels back in place, if you run it over to the driver's side and put it right up in between this lower panel and this side panel here, or side pocket here, it fits in there nice, and it doesn't smash your wire. You're going to have plenty to use on anything that you're towing.I'm going to come up here on the driver's side, go ahead and take the lid off your fuse panel, we're going to take our ten amp fuse that comes in our kit and we're going to install it in the towing position, which is going to be the third one up, right here. Go ahead and push that into place and make sure it's down in there well. Now we'll test out our wiring using part number I26. Left turn, right turn, brake lights, running lights.That'll do it for a look at installation on a Tekonsha T1 vehicle wiring harness with four pole flat trailer connector on our 2019 Toyota Highlander.



Will this #118449 work on a 2020 XLE Highlander?

Etrailer Expert

Chris R.


For your 2020 Toyota Highlander there's actually a different harness from Tekonsha, the part # TK74FR, that will work perfectly. The Tekonsha # 118449 shown above will not fit.

Info for this part was:

Employee Zack K
Video Edited:
Zack K
Employee Andrew K
Video Edited:
Andrew K
Employee Joshua S
Video Edited:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video Edited:
Chris R
Employee Jeff D
Installed by:
Jeff D
Employee Cole B
Installed by:
Cole B
Employee Nicholas E
Test Fit:
Nicholas E
Employee Randy B
Test Fit:
Randy B
Employee Brent H
Test Fit:
Brent H
Employee Shane H
Test Fit:
Shane H
Employee Robert C
Test Fit:
Robert C
Employee Andrew L
Video by:
Andrew L
Employee Kathleen M
Video by:
Kathleen M
Employee Jonathan Y
Video by:
Jonathan Y
Employee Michael B
Video by:
Michael B

At we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.

About Us
photos and videos
Original Photos & Videos

Produced to make sure you know what you are getting and you get exactly what you need.

Installations Completed

To make sure products work and fit the way they are supposed to.

etrailer call center
Phone Calls & Emails Answered

1,125,924 phone calls and 1,350,587 emails to help find the right solution.

etrailer training
Average Hours of Product Training

We get to know our products firsthand so experts can better help you.

etrailer service
Years of Quality Customer Service

Assisting our neighbors and customers, face to face at the counter.

etrailer experts
Pages of Expert Information

Created to make sure you have all the answers to your questions, from real experts.