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Trailer Wiring Harness Installation - 2013 Kia Soul

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How to Install a Trailer Wiring Harness on a 2013 Kia Soul


Today in our 2013 KIA Soul, we're going to take a look at and show you how to install the tow ready T1 vehicle wiring harness with the 4-pole flat trailer connector. Part number is 118637. This is what the wiring harness is going to look like when you pull it out of the package. We're going to have our T connectors . This is where it gets its name. Basically, we just separate the plug that goes right into the back of the taillight housing and this going to go right in line. So, this'll plug into the back of the taillight, this'll plug into our factory connector. The yellow and brown wire ...

This is going to be for the driver's side. The red and green . As you can see, it's longer. That's going to run all the way over to the passenger's side and connect behind that light. This is our 4-pole trailer connector. This is going to give us ground, running lights, turn signals and blinkers to our trailer or cargo carrier ...

Whatever we're going to be hooking it up to. We've got a ground wire here that we're going to be connecting and also a power wire. We'll just run this up to the driver's side underneath the hood to where our battery's located. To do that, we'll use the wire that's included. Also, the fuse holder and terminals .. Thing's like that that we're going to need there. Now, the heart of the system itself is going to be the modulite box.

What this box does is it's going to take the signals coming from the taillights and it converts it into a usable signal for our trailer. The nice thing about having the box included is that we're not drawing power through these wires to power our trailer. The power for that is going to come from our 12v power wire directly from our battery so we won't be overloading any of the circuits on our taillights. The first step for installation is going to be to open the hatch here. We need to remove the taillight housing. This is a big taillight housing ...

It's going to go from all the way up at this seam all the way down to this bottom seam. We've only got a lens and a small area of that, but we will be taking that whole panel out. To do that, we've got 3 phillips head screws that we're going to remove on both sides. We've got our connector here on the backside . We'll just press down that tab and separate it, just like that. We'll do the exact same thing over on the driver's side. Now, what we're going to do is take our yellow and brown wire here, connect it right into our factory connector. You want to hear that little audible click and then you'll be able to push and pull on it without it separating. We also want to find a convenient mounting location for our box. I'm going to go on the side wall here, right in this area. It seems like when we put our taillight housing into place, we won't have any interference there. What we're going to do is take a little bit of rubbing alcohol . Let's clean up our mounting surface. Also want to clean the back side of the modulite box. Once our rubbing alcohol's evaporated, we're going to take our provided foam tape, secure it to the back of the modulite, pull the other side off and we'll stick it right onto the side of the vehicle. Wiggle it around and make sure it sticks well. Now, we'll get our ground wire mounted. I'm going to take the provided self tapping screw and I'm going to make a hole. Once my hole is started there, I'll bring in my ground wire, place the self tapper right back into the hole we just created and then snug it down to make that connection. Now we've got our green and red wire. We're going to run that right down through the hole here that's created between the back of the body of the car and the bumper. Slide that right down through there and then gravity does a pretty good job of getting it right down where we want it. I have to kind of wiggle it a little bit. I'm going to do the same thing for my 4-pole wire. Now, on the passenger's side, we'll be able to use a coat hanger or stiff piece of wire. What I've got here is just a piece of airline tubing. I just want to push this down through that same hole we used on the driver's side. I'll do that before we go under the car . What this is going to allow me to do is attach that green and red T connector and pull it right up here where I need it. Now, we can head around to the underside. Now we'll reach right up behind the bumper there. Let's wrap the red and green wire over to the passenger's side. We can go up behind the bumper cover. I like to tuck it over really anything that I can to help keep it up. I'll zip tie it off right there after we get it routed. You can see our pull cable we sent down. We'll use just a little bit of electrical tape, we'll tape our T connector right off to it just like that. Just kind of stick that up there for right now. We'll be able to pull that when we go back up top to pull that up to make our connection. Now on this side, I'm going to use my 4-pole wire just like the red airline tube that we had on the other side. I'm going to take my black 12v wire, tape it off to it there. Then, if I pull on that from the top, it'll come right up along so we can make our connection there. We'll go ahead and pull our tubing here and bring our connector on up. Just like we did on the driver's side, we're going to plug that right into our factory connector. The other side of our T connector is going to go in our taillight housing itself. Now, we can put it back in place. Now, we can place our 3 screws back in here on the passenger. We'll head to the driver's side and make that final 12v connection. We can grab our 4-pole wire, gently pull up on that. We'll bring our 12v wire up. Now, we'll strip the end of our black wire. We're going to add on one of the provided butt connectors, crimp that. Then, we'll attach it to our red wire that's coming out of the modulite box. Now, just for a little bit of a moisture barrier, kind of a vapor barrier, we're going to go ahead and just wrap that up with some electrical tape. Grab the driver's side taillight housing and plug it in, then pop it in place. Now, we can route our 4-pole wire right over here to the middle where we'll be needing it for our hitch. What I'm going to do is just zip tie it as well as that green wire . That red and green wire off right here just to give us a good anchor point. Then, we'll trim off the excess. We're going to do that for any zip tie we put on like when I run our power wire up front. We can bring our 4-pole connector right over there to our hitch. It's got that dust cover included that's attached to it so I like to just use that as what holds it in place. Now, we're ready to run this 12v wire up toward the front of the vehicle. We run our wire up around the bottom side of the vehicle. What we're going to avoid are any moving parts, sharp edges, anything that might cause damage to our wire. I secured it right to our upper shock mount here and then over the top of the fuel tank. It comes out right here in front of the fuel tank and then I followed it along with our brake lines here. Then, from there, I rounded it just to the right side of the steering column, behind the brake lines here and right up towards the air filter box, just in front of that is going to be where our battery is located. What we're going to do is head up top and see if we can see our pull wire and pull it on through. Bring our wire through . Now, we want to confirm that we get all the wire pulled out. Last thing we want is a loop hanging down there dragging on the ground. Once we've done that, we use another zip tie. We want to anchor it off up here that way nothing can go from here down under the vehicle. Just going to go right to the brake line here coming out of the bottom of the master cylinder, it'll give us a good anchor point. We'll bring it right up. We're going to go right here to the positive side of the battery. You'll see we've got a couple studs there that we'll use. Trim that off. We can use our fuse holder, we're going to cut that at about the 4 o'clock position. Strip both ends of that off. To the long side of that, we're going to add a butt connector. That'll get connected to our black wire. To the short side of our fuse holder, we'll add our provided ring terminal. I'm going to route it right up underneath the cover here just like that. We can take the nut off the stud there, place the ring terminal on, flex it down a little bit and replace the nut. I'm going to coil up any of the excess here, we'll use a couple zip ties to kind of keep it all secured together. I'm going to use one to go through the hole in the fuse holder, around the coil of wire I created, and then also right around the batter cable so that way if they ever have to replace the battery and pull this off, then that'll come off and it'll just be attached to that cable so we won't have to worry about it. Now, we'll take our provided 10amp fuse, slide it in our fuse holder, and put our cap on. Now, we're ready to head back and test it out and make sure everything's working like it should. We're just going to plug in a test light here. When we turn on our headlights, you'll see the single red LED light up. Turn that off, now we'll check our left blinker. Should have a flashing LED. Now, our right blinker should look the same, just one over. And then finally our brakes. When we apply the brakes, both of the ones that just flashed should light up solid. All right, with everything working as it should, that's going to complete today's installation of the T1 vehicle wiring harness, part number 118637 on our 2013 KIA Soul.


Info for this part was:

Employee Andrew K
Video by:
Andrew K
Employee Joshua S
Video by:
Joshua S
Employee Kathleen M
Video by:
Kathleen M
Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video Edited:
Chris R
Employee Cole B
Installed by:
Cole B
Employee Randy B
Test Fit:
Randy B
Employee Robert C
Test Fit:
Robert C

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