T-One Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector

Video Transcript for T-One Vehicle Wiring Harness for Factory Tow Package Installation - 2024 GMC Terrain

Hello neighbors, it's Brad here at Etrailer, and today we're taking a look at installing the Tekonsha T-One, 4-Pole trailer wiring harness on a 2024 GMC Terrain. And this is gonna be a great option if you have a hitch on your terrain already because if you ever plan on pulling a trailer or a situation comes up that you need to pull a trailer, having that 4-pole trailer wiring harness means that you can safely and legally tow that trailer to get the light functions. Having this here means that you're able to plug into that trailer and get running lights, turn signals, and brake lights. And normally when it comes to wiring install, you do have to run this up to a battery to get 12 volt power, that's not the case here. This is a super easy installation because there's already a factory plug located in the rear of the fascia. It allows you to plug this in and once you zip tie it up, you're pretty well ready to go.

So, also it has relays in place to where it's gonna be protected. So if you get a back feed from your trailer, it's not gonna go back to any of your factory wiring on your vehicle and cause damage, so you're completely protected and you'll get all those safety features of having light function. So as far as that installation goes, I'll walk you through it just to make sure you get yours installed. And before we begin our installation, let's take a look at the wiring harness. So on this end we have a plug that's gonna go into a factory plug and that's gonna be located right about here, kind of by the bumper beam.

And that's pretty much the basics of plugging that. And the rest is just your 4-pole, which we can route over to our safety chain loop. And then we have these two plugs and the included relays. So out the gate we'll just take our relays, plug these in, make sure it snaps into place, and you'll see it's got this nice rubber grommet around there that makes sure that long-term water doesn't get in there. So make sure you press that together and it snaps in place.

And then to gain access to the plug, it's gonna be hard to see, but if you need a little bit of extra room, if you have larger forearms to get up to that plug, there's a T15 screw that's attached to a bracket here from the frame. So if we get that taken out, we can peel that fascia back a little bit and give us a little bit more access. Now on our plug there is a cap, which is nice. It's gonna keep it nice and protected from elements and that should make it a nice clean connection for our new plug. So we do need to remove that cap.

That red tab is gonna be a locking tab. So you'll slide that back, push on the tab to release the cap and get that removed. So this is what that cap will look like. You can see the red tab, and then you'll just, once that's popped back, just push on this and then pull from the other end of the plug and get that separated. Now I recommend holding onto this, that way if you ever change vehicles and you wanna maintain that wiring for whatever reason, you can cap that back up. It's completely up to you. But at this point we'll just grab our harness and we'll get that snapped in. And hearing that audible click means that we got that locked in place, and at this point, we just need to zip tie up everything nice and clean. So I'll go ahead and do that and show you how it looks. Now on the factory bracket where we had that T15 screw, there's a small hole here and that actually creates a nice little zip tie mounting point for a lot of our wire. And so I just kind of bundled that up and zip tied it together. The main thing is we wanna make sure it's not gonna be rattling around as we go down the road. And then from here, I just ran a large zip tie around our wiring to make sure that I have enough slack for our dust cap to go on our safety chain loop. And then once you have that all zip tied in place, you can get your T15 screw put back in, and then we just need to test to make sure that the wiring's working properly. And the test that it's working, we're gonna be using a 4-pole tester, which is gonna simulate hooking up to your trailer. So best way to do it, if you don't have a 4-pole tester, you can get one of these here at Etrailer or just hook up to the trailer that you'll be towing, and you're gonna hop in the vehicle, run through the light signals to make sure that they're transmitting to the taillights on the trailer. So running through our light signals. We'll start with our running lights. Next we'll do our left turn signal, our right turn signal, and then finally our brakes. Now. once to determine that it's working properly. All that's left to do is to cap this back on your safety chain loop using your dust cap. And that's just gonna keep it nice and clean until you're ready to use it again, and it's gonna be nice and secure as well. Other than that, that's gonna do it for the installation of our Tekonsha 4-Pole trailer wiring harness on our 2024 GMC Terrain.