Trailer Wiring Harness Installation - 2018 Toyota Highlander

Products Featured in this Video

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

874 reviews

Code: 118449

Retail: $76.43

Price:  $74.70

• Custom Fit Vehicle Wiring
• Trailer Hitch Wiring
• Converter
• Custom Fit

• 4 Flat
• Tekonsha

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring - no cutting, splicing or tapping required. Powered ModuLite reduces strain on wiring system.

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How to Install the Trailer Wiring Harness on a 2018 Toyota Highlander

Speaker 1: Today on our 2018 Toyota Highlander we're gonna be taking a look at and showing you how to install the Tekonsha T-One vehicle wiring harness with four-pole flat trailer connector, that's gonna be part number 118449.Here's what our wiring's gonna look like once we have it installed. It is gonna stay on the inside of the vehicle until we're ready to use it and it's gonna provide us with a four-pole flat trailer connector which is gonna give us all the required lights to get down the road safely and within the law such as our taillights, brake lights, and our turn signals. Whenever we're not towing we can simply take our wire, come to the hatch of our vehicle, and it'll store right here right by our spare tire tools so it'll be ready for us whenever we need our trailer.Now the nice thing about our wiring is that it's gonna be a simple installation and it's gonna be tailor made specifically for our Highlander. We're only gonna have a few connections to make and one fuse to put in underneath the hood and then we'll have our wiring ready.Now that we've seen what our wiring looks like and seen the end result let's show you how to get it installed. To begin our installation you want to come to your rear hatch and we're gonna take any kind of floor coverings like this mat and we're gonna fold them out of the way so that we can get access to the very back section here. Now we're gonna lift up on this panel and we are gonna remove it for now and set it aside.Now the plastic cover panel over here on the driver's side we're gonna remove as well.

That's gonna give us access to this panel and compartment right here. Now it's held in by clips so if we just grab the edge right here and pull up it'll pop out of the clips and we can remove it and set it aside.Now towards the front right where our spare tire tools are we're gonna have this carpet covering on the floor and we're gonna need to remove these pushpin fasteners. You're gonna grab a flat head screwdriver or a trim panel tool and we're just gonna pop them out and there's gonna be a total of seven of these spanning across the back of the vehicle. Now all the way over on the driver's side there is gonna be a 10 millimeter nut holding that plastic panel with our spare tire tools in place. You're gonna want to grab a 10 millimeter socket and pull that nut out.

Now the panel is only held in with clips now so we're gonna start here over on the side and we're gonna slowly work our way to the other side of the vehicle, just want to grab the panel and start pulling upwards which is gonna release the clips and once we have it loose we pull it out and set it aside.Now our wiring harness is gonna be a two piece section. First we'll start with our four-pole flat trailer end. We're gonna be looking for a four-pin connector which is gonna be on the back of the threshold here. Right by the latch on the inside we'll have our four-pin connector right here so we can take our harness and we can plug it directly in and make sure it locks in and give it a nice quick little tug. We can set the four-pole aside and now we're gonna be looking for a larger connector which should be right to the left or towards the driver's side of that original plug we just plugged in.

We can take our harness now and again plug it in, make sure it latches, now all we need to do is find a spot to mount our converter box and clean up the wires back here.Now there's gonna be a couple different ways that we can mount our converter box, we can use the double sided tape that is provided in our kit and stick it to a nice, flat surface provided that it is clean or we have an eyelet right here at the top to where we can take one of the included zip ties, pass it through, and tie it to some existing wiring. I'm gonna tie mine to some existing wiring back here because it would be nice and out of the way and I don't have to worry about it interfering with anything. Secure it with our zip tie, just want to make sure that once we have it secure that it's not gonna interfere with the panels that go in here.Now on our four-pole wiring I'm gonna route towards the driver's side, I'm actually gonna take all of my wires here on the driver's side and I'm just gonna take another one of those included zip ties and I'm gonna tie it to some of this factory wiring so it's nice and out of the way, then we can start to put our panels back in place. When you're putting your panels back just want to make sure that that carpet is on top of the spare tire tool compartment just like the way we took it out. You're wanna be extra careful lining up all the pushpins because you don't want to break any of those.My four-pole wiring I routed all the way over so I don't have to worry about it interfering or coming up through the panel because it'll be right here ready for us whenever we're ready to tow.

Put all our pushpins back in place and then we can replace that 10 millimeter nut over on the side panel. We need to put our panels back in place, just want to be careful of your wiring you don't want to put it right in line with those pushpins and damage the wire.With our wires ran back here we're gonna go ahead and need to go underneath the hood and put a fuse in place. Underneath the hood right behind our battery on the driver's side, all the way to the left, we're gonna find our fuse panel. We can just push onto this tab and remove the cover. Now if we come to the second row on the black section of our fuse panel if we come from the front we're gonna be looking for an open spot in between two seven and a half amp fuses. That's gonna be our towing port and if we look on our cover it will say that it's the towing section. We can take the provided 10 amps fuse in our kit and plug it in. Now we can go back and test our wiring.Now to make sure my wiring's working properly I'm gonna take my four-pole tester and if you need one of these you can pick one up on our website using part number I26. I'll grab an extra set of hands so they can run my lights and I can verify that they're all working properly. Can I have the headlights please Looks good. Left turn signal Right turn signal And the brakes Good. Can I get the brakes and both turn signals please All right with everything looking good we're ready to hook up to our trailer and hit the road.Now even though the wiring's on the inside I'm gonna go ahead and take the dust cap that is provided on there and go ahead and plug it up and we can keep our wiring right back here by our spare tire tools. Whenever we are ready to use our wiring we simply come to the cover, lift up, pull out the excess wire, and we're not gonna have to worry about the wire getting damaged from the hatch closing because we're gonna have this soft, rubber weather stripping which is gonna provide a lot of protection for the wire, provided that we just stay away from the latch itself.That'll finish up your look at the Tekonsha T-One vehicle wiring harness with four-pole flat trailer connector, part number 118449 on our 2018 Toyota Highlander.