bing tracking image

Trailer Wiring Harness Installation - 2015 Toyota Highlander

content loading

Products Featured in this Video

How to Install a Trailer Wiring Harness on a 2015 Toyota Highlander

Today on our 2015 Toyota Highlander, we're going to show you how to install the Tow Ready T1 vehicle wiring harness with the 4-pull flat trailer connector. Part number is 118449. Here's what the kit is going to come with when it arrives. It's going to have what we're after, our 4-pull trailer connector, so we can connect our trailer or any other lighting that we need operated in the back. That's got the 4-pin connector. That's going to go in right here in the rear of the vehicle.

Our other one is going to be the module box. This is going to send the power out and control everything for us. This has a 10-pin connector. That's also going to be installed back here in the rear. It's going to come with the fuse we need to go with the inline fuse holder here that's going to protect our lights and our vehicle's wiring.

Then we've also got the small fuse that's going to go underneath the dashboard and the fuse box up there. Now we're going to start by removing the coverings and stuff here in the rear, getting them out of the way where we can work. That'll just fold up out of the way. We've got the panel here. Let's set this aside. Also the side panel here will be set aside.

We also have this black box here in the corner. You grab it and just pull up on it. It should pop out. Let me just rotate that out. Right here there's going to be a bolt requiring a 10 millimeter socket that we're going to remove.

Now we can lift up our fascia cover. It'll just take a little pressure to get it pulled up and out of the way. Now we'll take our 10-pin plug and let's get it connected. Just give it the push pull, make sure it's nice and don't have any issues with it. What I'm going to do is just coil the wire like that. I'm going to grab my box. I'm going to zip tie it off right here. I'm going to keep good access for our fuse holder there in case we ever need to do any changes there. That'll be a good spot for it there. It'll keep it from making any contact with anything and creating any noise issues. Just trim off our excess zip tie, and I use the longer zip tie that comes with the kit for that connection. Now I'll just use one of the shorter ones here, bunch this together too. Then that'll stay nice and out of the way there. We'll leave our fuse holder open. We'll put that in in just a second. Now if we back up from there a little bit, we can put our 4-pin connector in. Just like the other side, that's just going to come down and click right in like that. Nice thing about this is you're going to have a little clip right there. Just push it right into that little body there, and that'll hold it in place for it, gives a nice, secure connection point. Now we can grab our larger 10-amp fuse, and we'll place it right into our fuse holder. Then we'll bring the cover over it and get it connected. That'll just tuck away right there. We'll know right where it's at if we need to get to it later. As we do this, we want our wire to be free of any of the small little tab areas here. We don't want to create a real bad pinch point or anything, so we'll keep it just outside of those. Get it lined up and then just push down firmly, get all our tabs back in place, and then we'll replace our nut. All right. We'll be done here in the rear of the vehicles, so we can start getting our panels all put back down here into place. The seat belt is going to go in between that and the side of the seat there. As you can see, our 4-pull is going to come out just fine. Now when we're ready for use, we can let that actually door close right down on there. That seal gives us enough room for that not to be pinched or damaged. With the door closed, it's going to close nicely there. We'll be able to come back and make our connection to whatever it is we want to connect to. When not in use, we'll lift our door up here, and then we'll just wad this up a little bit. Now there's 2 zip ties remaining in the kit that we didn't use. We only used 2 of the 4. You could use those to just hold this together. If you don't want to carry zip ties around you, you can also use this to wrap around there. That certainly isn't going to be as tight as a zip tie or anything, but it does do the job. We'll just keep everything together. We'll let that rest right there. Then when we close our door, it's just going to be out of the way. Out of sight out of mind things until we need it. Then we'll just pull open that panel to get in there to it. Let's go stick that fuse in under the dash, and we'll have this thing ramped up. Now we'll just press the tab there on the front, open up our cover. We'll set that aside. We'll take our small fuse. It's going to go right into the third slot up. You see you've got the 2 long, orange bars. Right at the end, you have a 10, a 7 1/2, and then we'll put in our 10. Put the cover back on. Now let's go test our wiring and make sure everything is working as it should. To test our wiring, we'll hook our ground or clamp to the white wire side here. That's our ground, so that'll test our ground. Then we're going to test our brown wire first. We should be getting a constant signal from that. Perfect. Now we'll check our left blinker. That should be the yellow wire, and that should give us a flashing signal. All right, 2 for 2. Now our green wire, that's going to be our right blinker. That should also give us a flashing signal. All right. Now we'll have our partner step on the brakes. That should give us a solid signal from both the yellow and green. All right. We've done our job properly. We're ready to hook up to our trailer, and we won't have to worry about the lights working. Now that everything is tested and secure, that's going to take care of the installation of the Tow Ready custom fit vehicle wiring harness, part number 118449 on our 2015 Toyota Hylander. .

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.