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Trailer Wiring Harness Installation - 2009 Toyota Highlander

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How to Install a Trailer Wiring Harness on a 2009 Toyota Highlander


Today on our 2009 Toyota Highlander, we're going to be doing an installation of the T1 Vehicle Wiring Harness with the 4-pole Flat Trailer Connector. The part number is 118449. Now, for the first step in our installation we need to plug in our module box that has the rectangular white connector on it and it's going to match up with the plug that we've got right up here. You see right here we've got the factory plug, so what we'll do is just take ours, line up our tabs, press it together until it clicks, and then pull to test. Make sure all of our connections are nice and tight and then we'll just tuck our module box up and use the provided zip tie to zip tie that off. I'm just going to go right around the wiring harness that runs right there.

That'll keep everything up nice and tidy and we won't have to worry about any noise or vibration from it. Trim off our excess. All right. That'll take care of inside the car. Now let's head to the back. We want to clear off enough space to where we can remove this rear-most panel.

We can just flip our mat up and out just like that. Pop that panel off. Now we're going to be putting all these panels back in place so you'll want to hang onto them. We got the one here on the side. Bring that out.

Then we're also going to grab right here and we'll lift up on this and that'll separate the one, two, three, four, and five push fasteners. That we'll also set out of the way. That gives us access to the compartment we need to remove. To remove it we'll do the push-pin fastener here. We'll be reusing that, so hang onto it.

We're also going to remove the two . They're a push fastener but they unthread, so we just want to loosen those up. All right. Then we can just lift up on this compartment and get it out of the way. Located right behind that compartment you're going to have a little square plug. That's going to match the one that's on our 4-pole. That's the green, yellow, blue and white wire. Let's make that connection. Then we'll give it a push-pull just to check and make sure everything's nice and tight. Now we'll tuck our 4-pole wire right through the little slit right there, give us a little room and we'll just let it hang out here while we put our stuff back together. Start by putting in the compartment we removed. We're going to make sure that's not going to pinch our wire or anything, so make sure it's got some clearance and we can push down on that, line up our fasteners in the bottom. All we have to do with these is just push down and they'll slide right on the studs that stick up. All right. Then we remember our push-pin fastener here. We'll put that back in. Now it's time for our panels to go back in. Get the one here. We'll just line up the fasteners with the holes, go across like that, push them down and in. The side panel back in and then finally the one here at the very back. There, mat back and that's really all there is to the install. Now as far as storage goes when not in use, we can kind of gather this together so it's not going all over our car. We'll bring the plug end around the wiring and then we just cap that off. That'll allow us to tuck it over here, keep it out of the way and we only really pull it out when we need it. Then we can just uncap it, drape it right out of the rear of the vehicle here as you see. The nice thing is that the weather stripping that goes around the door gives us plenty of cushion room for that to fit right in. We can put our top back on, and our mat. Then when we close our door, as long as we avoid the pinch point here at the catch, we won't have any problems. Now we're ready to put in our fuse to power everything up and give us the lights we need at the connector. To do that, we'll pull off the cover here. You can see the two long orange pieces here. There's a little gap right there just beside those. It's the second fuse up. It'll be labeled in your cover. You'll have the 15A for amp, then right below that is towing. We'll slide the 10-amp fuse there and that's going to stick up a little bit but no big deal. It does the same job. We'll put the cover back on our panel here and then let's go test them out, and make sure everything's working as it should. Now to test our plug, what we'll do is take a test light and we're going to connect the ground clamp to the ground wire. That's going to make sure that that has a good ground and that it'll support our lights. We've got the running lights on, so on our brown wire we should have a constant signal. Perfect. Now, if we ask our partner to turn on the left blinker we should have a flashing signal coming from our yellow wire. Perfect. Now the green wire, that'll be our right blinker. Now from those same two wires, once they stand on the brakes, we should have a constant, steady signal. All right. Perfect. Everything's working as it should. We can either hook up to our trailer or tuck this away until we need it. 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 2009 Toyota Highlander. .


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

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