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Curt T-Connector Vehicle Wiring Harness Installation - 2021 Hyundai Tucson

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How to Install the Curt T-Connector Vehicle Wiring Harness on a 2021 Hyundai Tucson


Hey everybody, how's it going Today, we're gonna be going over, and showing you how to install, the Curt T-Connector Wiring Harness, here on a 2021 Hyundai Tucson. So, our trailer wiring harness is gonna be required when we're towing a trailer, because we need a way to transmit the signals from the vehicle to the trailer behind us, to let others out on the road, know what we're gonna be doing. It is required by law in every state. We can also utilize a trailer wiring harness, if we have any such sort of cargo carrier, or bike rack with integrated lights. A lot of these can actually block the vehicle's tail lights, which is illegal. Therefore, they have integrated lights, and we can utilize those with our trailer connector.

So, there's a few different types of trailer connectors on the market. Probably the most common and basic one is gonna be the four-pole flat, that we have here. That's gonna accommodate most smaller trailers. Now there are some other larger trailers out there that have electric brakes. And if it does have electric brakes, you're actually gonna need a seven-way.

We do offer some adapters to adapt this from a four-way to a seven-way, if that's what your trailer has. So, here you can see that we have the trailer connector secured to the safety chain loops on our trailer hitch here. When we're ready to use it, we would simply just undo that, bring it out here, and that way we can plug it into the trailer connector on our trailer. So, this is gonna be the most economical option to secure this. There is, however, another method.

You can purchase a series of brackets, that we sell at etrailer here, and they're actually gonna let you permanently mount the trailer connector to the actual trailer hitch body. It makes for a little bit of a nicer finish, but you obviously need to purchase a couple more brackets as well. So, the choice is up to you. Either option is gonna work great. There are a couple of nice things about this kit, specifically.

Number one, it offers complete plug-and-play installation, so we don't have to do any splicing into our factory taillight circuits. It's also gonna have a powered module. Therefore, the lights on our trailer aren't actually gonna be drawing any power from the taillights. They're gonna be drawing it from the vehicle's battery. They're simply gonna be receiving the signal for our taillights. This also means that any issues we have on the trailer, won't have a chance of effecting our vehicle here, and causing any damage. So, now that we've gone over a little bit about the wiring harness, let's go ahead, and jump into the installation. You guys can definitely do this one at home, and we'll show you how step by step now. So, we need to remove our taillights, and the first step to do that, is to open the hatch, come inside here, to either side. We're gonna have this little black plastic cover. We need to remove that. That's gonna reveal the screws, which are holding the taillight to the body. So, we're just gonna be taking a plastic trim panel tool here, and we're just gonna be prying up along the outside edges here, in order to free that panel. You wanna be careful not to break any of the tabs in there. So, just go ahead, and take your time, slowly work your way around. Now, once we have that cover removed, we'll take a 10 millimeter socket, we'll remove the two screws here. And, once these are out, we should be able to pull the tail light out and away. There are some alignment tabs there, which make it a pretty tight fit. But, once we get it out here, we're gonna remove the connector. Simply depress that tab right there, and we should be able to pull out. And we'll simply just repeat that same process on the other side. So, now starting over on the driver's side here, we're gonna be taking some sort of pull wire. We're gonna be using a piece of airline tubing. We're simply gonna stick it down to that opening in our taillight pocket here. We won't be able to come out underneath all the way yet, 'cause there'll be a panel in the way. We wanna get, make sure we get our airline down there. When we do remove that panel, we can easily just reach up there and grab that. So, the next thing we're gonna do is, we're gonna actually take our wiring harness here. We're gonna be taking the connector here, with the brown, yellow, and red wires, we're gonna tape that to our airline tubing, that we ran down through here. Now, you will need to remove this panel first. There's gonna be three fasteners, one here, one here, and one on the inside. They're just those pushpin fasteners. We'll just release the center of them. And then we can pull this panel straight out. And then that's when you'll tape it to your airline tubing. Now we'll go back up top there, we'll pull our airline tubing through the taillight pocket, so we can fish our connectors behind there. Now, that we have our two connectors here up into the taillight housing area, we're gonna plug one of them into the factory connector on the vehicle. It should only go in one way. We should hear it click when it locks into place, and now we'll take the other end here, we'll actually attach that to the back of our taillight. And now, we can go ahead and reinstall our taillight here. You may need to actually push the connectors down at that little opening there, to get everything to fit. Now we'll just simply reinstall our cover. So, now we're gonna come back underneath here. And at this point, we're gonna mount our converter box. So, in our kit here, you're gonna get some double sided tape we can attach to the back of that. Then find a surface to stick it on up here with. However, I really recommend using this, utilizing this little tab at the top here, and getting a self tapping screw. You do have one that comes in your kit, but we're gonna need to use that for the ground. So, you'll need an extra self-tapping screw if you wanna secure it this method. Either is fine. I just prefer this one, using the self-tapping screw, 'cause it's a little bit more sturdy. Basically, I'm just gonna attach it to this little flange here, just like that. You can see, it's nice and solid now. Now, we'll take our white wire here. We're gonna go ahead and ground this to a bare piece of metal there, using our self-tapping screw. So, we're just gonna come up here, but really any bare metal surface in this area will be fine. Now, we're gonna take our other connector here, with the green bundle of wires coming from the converter box. We're gonna route that from the driver's side, over to the passenger's side there, and then we're gonna use the same method to get it into the taillight pocket, and then plug it into our actual taillight. So, here's our green wire here. You wanna make sure you give yourself some slack here, because we have our panel that has to go back on. So, what we did, is it just came over here, and if you have your trailer hitch installed, we just routed it over the cross tube, and then into this little pocket here. We're gonna have some factory wires here, running alongside the back of our bumper. We just simply used a zip tie to secure it to these factory wiring harness, every few inches or so. It comes over here, and then, when we get to this part here, we need to be really careful, 'cause our exhaust is right here. So, there's gonna be a little metal bracket here, we're gonna go over that. And then we're gonna route it past the other side here, down into this pocket. Keep in mind, we do have to remove that panel here. We showed you how to do that earlier, but here we have the remaining green wire in our connectors. We're simply gonna use that pull wire we used earlier, fish it down behind the bumper, so we can tie it to that, and then pull it up through. So, now we're gonna take our bounded four-pole here. This is what it looks like. You're gonna unravel it. And, we're actually gonna be routing this over to about where the receiver tube is on our trailer hitch. We'll probably use the same path that we routed the green wire earlier, to get to about the midway point, and then we'll secure it to the safety chain tabs here, on the trailer hitch, using the included dust cap. There is also an alternative method. We can purchase a series of brackets to attach it to the hitch tube as well, whichever you prefer. The series of brackets is gonna be a little bit permanent, more of a nicer finish, but it'll work just as fine, and save us some money if we wanna attach it to the safety chain tab. So, here you can see we have our four-pole mounted and secured to the safety chain loops, using the dust cap that comes in our kit. I went ahead, and just tied it to the existing wiring, that's already back behind the bumper there. I actually went back and forth a few times, since we're gonna have plenty of extra. But now, what we're gonna do next is, we should have one other wire coming from our converter box, which is this black wire here. That's gonna be the power wire. We're gonna run this to the battery, which is located in the engine bay. So, we're going to crimp on a yellow butt connector. And then we're gonna attach one end of the bundle of wire, that came in our kit here, looks like this. We'll first need to strip back a few millimeters here, off the jacket, and then we'll clip it into the other end of the butt connector. Once we have that done, I'm gonna go ahead, and route the wire up to the engine bay here. We'll do that now, and then we'll show you the path we took. Once I'm done there, I'm gonna finish cleaning up the extra wires that we have hanging down here, and reinstalling our panel on both sides. So, between our fabric liner here, and this plastic panel, we have our power wire routing out from the converter box, which is behind here. Now, we came up and over the sub frame here, there's two sections of it. And then we should see some brake lines here. We went ahead and zip-tied our power wire to these brake lines. We have it zip-tied a couple more places here, and here. And, so we're gonna run along here, all the way to our brake lines, under this panel here. So, you're gonna need a 10 millimeter socket. There's gonna be one screw here, one screw here. We're gonna remove those, and tilt down our panel. And then we're gonna have access to the brake lines, that we can continue securing our power wire to, all the way up until we exit, right here. I went ahead and routed the power wire over these little support brackets, here and here. And through here, as we can see, and then I have it ran up into the engine bay. In order to get it up there, you're gonna want to go ahead and take some sort of pull wire, fish it down through the engine bay, bring it out in this area. Then you can tie your power wire to that, and then pull it up into the engine bay. So, once we have our power wire ran up into the engine bay here, you're gonna use a couple of zip ties to secure it to the existing wiring. That way the wire doesn't fall back down, getting in the way of the steering, or the exhaust, or anything. But, then we're gonna route it over to the positive terminal or battery, which is gonna be located straight here. We're gonna have a cover on there. So, we're gonna have our wire ran over to the positive battery terminal. What we're gonna do is, we're gonna cut off the excess. So, we're not gonna need that. And now what we're gonna do is, we're gonna take our fuse holder here, that comes in our kit. We're gonna have some excess on there as well, that I'm gonna cut off. And then what we're gonna do is, we're gonna take the ring terminal here, that comes in our kit. So, it looks like this. We're gonna crimp that on to one end of the fuse holder. And then we are gonna crimp on a butt connector to the other end, and attach that to our power wire. Once we get that crimped on there, what we're gonna do next is, we're gonna take a 10 millimeter socket, we're gonna remove this nut here. Make sure we don't lose that nut down the engine bay. And then we're simply gonna attach the ring terminal of our fuse holder to that, and resecure it with a factory nut. And what you'll notice is, if we try to close the lid, that ring terminal there, is gonna get in the way. So I'm gonna mark where it is, and I'm gonna take a pair of snips here. I'm just gonna cut a little slot in there, to allow clearance of the ring terminal, when we shut the lid. Just like that. Now, we're gonna go ahead and insert our fuse into the fuse holder. Now, we're gonna go ahead and plug in our four-pole tester. If you have your trailer nearby, you can use that as well. We're gonna use this to test out all of our lights, to make sure all our functions are working. We have our brakes, left turn, right turn, and then finally, tail lights. And that's gonna do it today for our look and installation of the Curt T-Connector Trailer Wiring Harness, here on our 2021 Hyundai Tucson..


Info for this part was:

Employee Kathleen M
Installed by:
Kathleen M
Employee Chris R
Video Edited:
Chris R
Employee Jonathan Y
Video by:
Jonathan Y
Employee Conner L
Test Fit:
Conner L

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