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Tekonsha T-One Vehicle Wiring Harness Installation - 2020 Jeep Wrangler Unlimited

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How to Install the Tekonsha T-One Vehicle Wiring Harness on a 2020 Jeep Wrangler Unlimited


Connor: Hey guys, Connor here at etrailer.com. Today we're going to be taking a look at the Tekonsha T-One Vehicle Wiring Harness here for our 2020 Jeep Wrangler Unlimited. So our T-One vehicle wiring harness here is going to be an excellent option for our Jeep Wrangler. It's going to provide us with a four pole trailer connector, which is going to be the most common trailer connector that we're going to see on small trailers, as well as some cargo carriers if they have lights installed. Now the four-pole trailer connector is going to provide us with a running light circuit, a left and right stop and turn signal circuits as well. Again, most smaller trailers are going to be using this type of connector.

So as you can see here, we have this nice little dust cap, which is going to go over our four-pole connectors here. It's going to keep the pins free of any corrosion, which then can in turn create lighting problems.So in regards to installation, our T-One harness here is going to be completely plug and play. We don't have to worry about splicing into any of the vehicle's factory taillight circuits. It's simply going to plug into connectors behind our taillight housings. We have to ground the converter box, and then we have to run a power wire up to the vehicle's battery.

Again, this is something that's very simple, pretty straight forward, something you can definitely do at home by yourself with only common tools required. Me personally, I prefer the T-One Vehicle Wiring Harness, although there are others available. However, my experience has led me to believe that these are most reliable because the converter boxes are a little bit more secure and sound. We don't have to worry about the wires being pulled out if the converter box did come loose from the vehicle.So now that we've gone over some of the benefits and features, let's jump right in and show you how easy this is to install yourself. So the first step of our installation here, we need to remove our taillights.

In order to remove our taillights, we need to come in the inside of the hatch here. There's going to be bolt as well as a trim panel cover we need to remove. So what we need to do is take a trim panel remover tool, we're using a pick here, a flat blade screwdriver would work as well. We just need to remove that. And we want to come back here with a 10-millimeter socket.

We see we have this little bolt here that we need to remove. This is what's holding our taillight assembly onto the vehicle so we, again, need to take our 10-millimeter socket and just remove this.I'm actually using my other hand on the outside of the vehicle to press against the taillight so it doesn't fall, and there's our bolt. So now that we have our 10-millimeter bolt, remove our taillight housing should just pull straight off the vehicle. Keep in mind we just want to pull it straight back so we don't damage any of the alignment tabs. So as you can see there, it's pretty easy to take off. Now we're going to want to take a look at the backside of our taillight assembly here. We see we have our factory pigtails. What we want to do is we want to release that locking tab there by pulling it out away from the taillight assembly. And then what we need to do is we need to depress the center portion here. We need to pull out on our connector away from the taillight to release it from the assembly.Now they can be a little tough to remove, I will admit, so we just have to work at it here, but essentially, we're just going to be depressing that tab here and pulling out. So I found it's kind of hard to get these little tabs depressed enough to pull the taillight pigtail out. So what I'm going to do is I'm just going to take a flat blade screwdriver here and press it down and then I can pull out. As you can see here, we have one little tab that's holding the taillight assembly here onto our wiring harness. We're just going to take a flat blade screwdriver or a trim panel removal tool. We're just going to pry that free from the taillight housing, just like that. Now we can set this aside and repeat that process on the other side.Once we have the taillight assemblies off the vehicle, we can go ahead and take our wiring harness here and begin to make our first connection. We're going to be on the driver's side of the vehicle here. We're going to be taking the pigtail with our yellow wire. What we want to do is we want to take the part of our factory harness, and we want to plug it into the opposite end of the pigtail on our wiring harness. Once we hear the audible click, we know it's secure in place, then we can go ahead and depress our locking tab.So now that we have our driver's side connection made, we need to go ahead and work our way to the passenger side using the pigtail with the green wire. Now in order to get our connector over the passenger side here, we're going to see a little pocket behind the factory taillight assembly down there and that's where we're going to run our connector through so we can route it to the other side. So I'm just going to take our connector up, so, sort of just push it down in that hole there, feed some of our wire through, and then we're going to go underneath and try to grab that and route it to the other side of the vehicle.Now if we take a look on the underside of the vehicle here, we're going to see the bundle of wires that we tucked down into the taillight pocket. I'm just going to reach up in there and grab those until we have our connector, pull out the remainder of the wiring harness and now we can begin to route this over to the passenger side of the vehicle. So before we secure the rest of our wire up, we're going to show you how to get the passenger side taillight connector into the passenger side taillight housing. So if you remember similar to how we had on the driver's side, there's going to be a pocket behind the taillight assembly. However, since we're going up and over rather than down and under, we want to take our wiring harness here, and we want to shove it into the pocket, and then we want to loop it forward up into the taillight assembly. So I'll try to do this now. So I'm going to go in that little pocket that we did earlier there, and we really want to try to feed it up just over that lip there.So it looks like we've got most of it there. So now let's go ahead and make that connection and we can finish securing our wire. So now that we're on the passenger side taillight pocket and it does look a little bit different than our driver one there, is that we have more backing. It's not quite as visible behind, but if we can see that green wire there. So we know we have the pigtail behind the passenger taillight housing here. We're just going to need to take something so we can grab that wire and then run it through our hole right here. I'm taking my finger here. Once I have it around the green wire, I'm going to do my best to try to feed it and get both of the connectors through this opening here, just like that.Now we can go ahead and make our connection again, wait until you hear the audible click, and then depress the red safety tab. Now we're going to go underneath. We're going to finish securing our green wire here. Now to get our green wire, we want to make sure we mount it so it's away from our exhaust here because, again, we want to make sure our wire isn't near any moving parts or our exhaust from heat. So what I'm going to do is I'm just going to take it, I'm going to wrap it around the body mount on top there. I'm also going to wrap it around our tow hoop here. I'm just going to push it up there, we're going to hold some tension, and now we're going to use some zip ties and we're going to secure it to our crossmember here.So what I'm going to do is I'm just going to take a zip tie. There's already a hole there. Keep in mind if you have a trailer hitch, you may just need to route the zip tie around the entire cross-section there because these holes may not be present. So what I'm going to do is I'm just going to take a zip tie here, place it through that hole. I'm going to use this to secure the green wire so it's not dangling around. Keep in mind, if your zip tie's long enough, you can just combine two together. So we're going to loop our green wire through there. We're going to tighten our zip tie. We're going to tension the green wire to so we make sure it's not hanging down further back towards the taillight assembly. We're going to close the zip tie. You can see there, we have our green wire nice and secure so we don't have to worry about it dangling down. I'm just going to cut the end of our tie off here.So as you can see here, we have two zip ties on the crossbeam here. We have the remaining of our green wire here, which as you can see, it hangs down pretty low and it's going to get kind of close to our exhaust. So what we're going to do is we're going to be taking some wire loom here. Keep in mind, this doesn't come with the kit. We're basically just going to be using this to sort of shield the wire away from our exhaust. And then we're going to use one of our factory holes here to secure it to the frame. So this part isn't required, just some extra precaution we're using to stay away from the heat.I'll just go ahead and cut the ends of our zip ties here. Now as you can see, we're a good four or five inches away from our exhaust, so that should offer enough protection to shield our wire from heat. So our next step here is to secure our converter box, but before we do that, we want to go ahead and just loosely attach our power wire, which gets attached to the black wire from the converter box and then gets run to the battery. So what we're going to do is we're going to take our butt connectors, which are included with the kit. Yours may look a bit different. I'm just going to crimp that onto our power wire there. We're going to crimp the other end on the other side of the power wire coming from our converter box.And I always just like to give our crimps a nice little tug, just to make sure they're seated properly. What I'm going to do next is I'm going to find the other end of our power wire here. We're going to try to fish it down through that hole that we routed our green wire through there earlier. So now we have our power wire here, which we looped down through the bottom of the vehicle earlier. So we're going to go ahead and run this up to the battery. We'll show you how we did that after we've done so. Keep in mind, you want to steer clear of any moving parts as well as the exhaust.So as you can see, we have our power wire coming here behind the pocket from our taillight housing. We ran it down. We have it going to the bottom side of the frame rail. I see our power wire ran up here. We went ahead and went over the shock mount, through the coil spring mount here above the subframe assembly. We have it tied to an existing wiring harness here to hold it in place and keep it away from our exhaust. Then we came out right here above the subframe assembly and above our coil spring mount. We have our wire zip tied to our brake lines. To begin, just follow our brake lines. I left the zip ties intact to show you where we secured it at. And now we come to the heat sleeve here because we get close to our exhaust. So what I did is I tucked the power wire behind the sleeve and I zip tied it to it every couple of feet or so. So again, just following the power wire up to the front where our battery is. You can't really see it because, again, I have it tucked behind the heat shield, so it's shielded from our exhaust here, with some zip ties to secure it in place.And we can see the rest of our power wire coming down here. We have our catalytic converters right in this area here, so it gets very hot. We need to make sure we steer clear of that. But in order to get our power wire up into the engine cavity to our battery, we're going to go up top and we're going to take a pull wire with our airline tubing. We're going to fish it down through the engine bay, and then we're going to tie the airline tubing to the end of our power wire here. That way when we pull the airline tubing through the engine bay, that's going to allow us our power wire to be up near the battery.So now as we mentioned, we're going to take a piece of airline tubing here. We're going to fish it down to the bottom of the engine bay. So again here by the brake booster, we're just going to feed our wire down to the opening there. I can already see our power wire. I'm just going to feed that down there, like so. We're going to keep the other end of our power wire, tuck it away so we make sure it doesn't fall through. So we can see here, we have our other end of the power wire and then we have our red pole wire, which is dangling to the bottom of the engine bay here. I'm just going to take the two, tape them together with some electrical tape. And then when we pull our pull wire through the engine bay, our power wire will come up with it.As you can see here, we have our power wire. I'm going to route it over here because we want to make sure we steer clear of any of the exhaust components, as they get very hot. And as we noticed, our battery is actually going to be on the passenger side, so what we're going to have to do is we're going to have to take our power wire here, we're going to have to round it up and over this little cowl here to our battery. So I'm going to use some of our factory attachment tabs here to secure our power wire and allow us to route it over to the passenger side of the vehicle. We have a couple more tabs we can use here, as well.Now I'm going to apply tension to our power wire here to get rid of all the slack we have. I'm going to use a zip tie to secure it to our last factory attachment point here. That way, we don't have to worry about the wire drooping down over time. Now we can take the end of power wire here. We can go ahead and strip some of the jacket off. We can use one of our butt connectors, again, these are included with the kit, crimp this onto our power wire, and the other end is going to go to a fuse holder, which is also included with the kit. However, yours may look a little bit different than the one we're using here today.So again, we're going to remove a little bit of the jacket, place one end into the butt connector here, crimp that in place. Then we can attach a ring terminal. And now we need to find a good post on the battery to attach our power wire to. And we have this closest post to the cap here. That's going to be a 10-millimeter nut. We're going to go ahead and use that one. I'm going to remove the nut, place our ring terminal over the stud there, put our nut back on, and tighten everything down, just like that.Now that we have the power wire ran, our next thing we need to do is we're going to need to attach our ground wire. Now we have two options for attaching our ground wire. You can use a self-tapping screw, which is included with the kit, or we can simply just run it into a bare metal spot on our body here. However, since it isn't the best idea to go ahead and drill holes into a new vehicle, we can go ahead and use one of these studs we have down here. It's just a miscellaneous nut which we may have laying around. All we need to do is simply stick our ring terminal over that stud there, take our nut, thread it on, and then tighten it down, just like that.Now finally, we can go ahead and mount our converter box here using our double-sided adhesive backing which comes with the kit. We need to pick a location that's going to allow for our taillight to be re-installed back on the vehicle. So there's going to be a nice flat surface back here, which we can mount our converter box too. That's where I'm going to go ahead and place it. Once we get on the surface, we want to go ahead and just hold it in place. Press firmly to let the adhesive seal properly for a couple seconds or so.So before we reinstall our taillights, we want to take our four pole connector here. We're going to route it to that same hole that we ran our power wire and our green wire to the passenger side taillight through. So again, sort of running in there like so. We can come underneath, and pull the rest of our wire through.Now that we have our converter box secure, we can go ahead and reattach our taillight assemblies. The connectors only go one way, so it should be fairly easy to figure out. Push the two together. We should hear the click. Then we can reengage our locking tab. Now we can set the assembly back on the body of the vehicle. Keep in mind, we may need to push the connectors back into the opening there so they don't interfere. We have two alignment tabs on the side. It should go back in place pretty easy. We can take our bolt that we removed earlier, just pop it back into place. We can use our 10-millimeter socket to secure it. It doesn't need to be real tight. Just give it a nice little wiggle on the taillight to make sure it's secure, and then we can go ahead and reinstall our plastic cover piece. Once that's in, we can go ahead and repeat this process on the other side of the vehicle. Now last but not least, we can take our 15 amp fuse, which is again included, insert it into the fuse holder, put our cover back on.So before we test our trailer lights here, we actually need to go ahead and mount our four pole connector. There's going to be a couple of ways to do this. We're going to need to bring it to our hitch cross tube, so I'm just going to bring it back and loop it around the safety chain loop, similar to how we did with the passenger side taillight connector. Then we're going to come here in front of our crossbeam, and this is where you have a bit of a choice: one option for a permanent installation, you can purchase a series of mounting brackets here from etrailer. They're no-drill mounting brackets, so we don't have to drill into anything on the vehicle, and that's going to permanently mount our trailer connector to this crossbeam here. However, the most cost-effective solution, which is what we're going to use here today, we're simply going to route the wiring harness around our hitch cross tube here to take up some of the slack. Then we're going to leave our four pole wiring harness dangling here so we have access to it.Keep in mind, we do want to make sure we steer clear of our exhaust muffler here. So we went ahead and, again, used a couple zip ties to secure the slack of our four pole wiring harness to the cross tube here on the vehicle. Now we can go ahead and attach our four pole tester and test the lights. Keep in mind, we do sell these here at etrailer. They are not included with the kit. Or, if you have your trailer on hand, you could use that as well.Now that we have everything installed, we can go ahead and test our trailer lights here to make sure everything's working correctly. We're going to apply our brakes to see that we have the brake lights. We're going to apply the left turn signal, right turn signal, and then our taillights.Now that we've tested all our lights, we've ensured everything's working. That's going to do it today for the Tekonsha T-One vehicle wiring harness here for our 2020 Jeep Wrangler unlimited.


Questions and Comments about this Video

Michael B.

Thank you for the informative video. Will this wiring kit work in conjunction with a flat tow kit (Stay-N-Play braking / Roadmaster Baseplate) where the harness is already utilized? I wasn't sure if you could daisy chain the plugs or if you have to splice wiring.

Etrailer Expert
Reply from Les D.

@MichaelB the Tekonsha # 118786 part you are referring to is to put brake lights on a trailer being pulled by a vehicle. If you wish to flat tow a vehicle behind an RV you would want a harness made for your vehicle. For instance, if you were flat towing at 2021 Jeep Cherokee you would use the Roadmaster # RM-154 kit. If you can provide me the year, make, and model of vehicle you wish to tow I can look up a confirmed fit for you.

Reply from Michael B.

@LesD Sorry, I guess I wasn't clear in my question. My 2019 Jeep Wrangler JLU is already set up to flat tow behind my motorhome and the harness on the taillight is already being utilized. I wanted to set the Jeep up to tow a trailer and wondered if I could use part # 118786 in tandem with the flat tow harness. I.E. the flat tow harness plugs into the trailer harness which plugs into the taillight harness.

Etrailer Expert
Reply from Les D.

@MIchaelB OK, yes, I am with you now. To create a flat 4-way trailer lighting harness on the back of your Jeep you would use the Tekonsha # 118786 wiring harness. This kit plugs directly into the factory receptacle on the back of the tail light housing. The wiring/diodes splice in to the factory wiring coming from the front.

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