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Trailer Wiring Harness Installation - 2012 Hyundai Tucson

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How to Install a Trailer Wiring Harness on a 2012 Hyundai Tucson

Today on this 2012 Hyundai Tucson, we're going to install part number 118501 from Tow Ready. First thing we need to do is go ahead and open up the back hatch, and then we need to remove the tail lights. There will be 2 screws that we have to remove for our tail lights. Once the screws are removed, we need to pull straight back on the tail light to release it from the body work. There's a small tab we have to push down, and then we can release it and pull it away. Then we'll go ahead and set the tail light away for now.

We'll go ahead and repeat the same process over on the passenger side. Now we need to get inside the vehicle and remove the floor coverings to get down to the spare tire. To remove the threshold, there are 3 plastic fasteners that we have to unscrew the centers and pull them out. Then using a steady pressure, pulling straight up, we can go ahead and release the threshold from the clips. We'll put that aside for now. Okay, now we can go ahead and start to install our wire harness.

First we need to take a fish wire and run it from underneath the vehicle into the interior of the car. So we'll go underneath the vehicle, and there's a large grommet there we have to remove. Then we'll go ahead and take our fish wire and run it through. Now our fish wire in this case is going to be a plastic air line tubing. So we'll go ahead and run it through the hole, and then we'll go ahead and run it behind the interior paneling, and then we'll go ahead and pull it out from underneath.

There's a small opening towards the back edge that we can reach in and pull it out if necessary. Now we'll take the 2 ends of the T connectors, 1 end with the yellow wire, and 1 with the green wire. We'll go ahead and take these 2 connectors and temporarily connect them together. We'll go ahead and tape these 2 to our air line tubing, and gently pull it back through. Now our converter box will also be pulled to the inside, as well as our white wire for our ring terminal. Be careful when you pull on the module with the white wire to make sure you don't lose it.

Now we'll pull out all the wiring until we get down to the rubber grommet that's built into the kit. Then we'll go ahead and seat that into the hole. Now we'll go ahead and start routing our wires to the tail lights. We'll take our air line tubing and run it from the opening from the tail light down to the bottom. We'll tape it to the T connector with the yellow wire, and pull it up through. Once we have it pulled through, we'll go ahead and connect it to the factory wire harness, and then we'll plug it into the back of the tail light. At this point, we can go ahead and reinstall our tail light. Now to our other T connector end, we're going to take our air line tubing and run it through the bumper structure. This is the steel part right behind the plastic bumper cover. We'll go ahead and run it all the way through until we hit the other side. Then we'll tape our T connector to that and pull it on through. Then once again, we'll go ahead and route the T connector back up to the tail light on the passenger side. We'll go ahead and pull it up, take care of the slack, and then zip tie it to the existing wire harness. Once again, we'll make our connections to the T connector, to the factory wiring harness, and then the other end will go to the tail light. We'll go ahead and reinstall our tail light now. Now we'll go back to the interior of our vehicle and do this with our white wire with the ring terminal. Now we're going to use an area where 2 pieces of sheet metal are overlapping. This will give us more material to drill into. We'll use the self-tapping screw that comes with the kit and attach it to the sheet metal. Okay, at this point, we can go ahead and reinstall our interior panels as well. We'll go ahead and reinstall our threshold, as well as our floor panels. Now we'll make sure that we take our 4-pole connector, and we'll leave it on the interior of the vehicle for now. Okay, back underneath the vehicle, we'll go ahead and connect the black wire that comes with the kit, using the yellow bud connector, to the red bear wire. We'll go ahead and take our black wire, and connect it to the red wire just below the new grommet that we installed. Then we'll go ahead and tape it up. Then we'll go ahead and continue running our black wire all the way up to the front to the battery. As we run it along, we'll go ahead and zip tie it along some factory lines running over the rear suspension. We'll continue following the lines going all the way up front, zip tying periodically. Then we'll take our air line tubing, and we'll go ahead and connect that to our black wire. With our line secured underneath the vehicle, we'll go ahead and open up the hood. We'll reach down and pull out our air line tubing with our black wire. We'll run it up behind the components, behind the battery, and around so we have a good place to zip tie it to. Then we'll take our wire, and measure our length, and cut off our excess that goes up to the positive battery terminal. Then we'll go ahead and get our fuse holder that comes with the kit. We'll cut it in half, and a bud connector to the other for black wire. We'll take our yellow wire from the fuse holder and sneak it up underneath the cover that goes over to the positive battery terminal. We'll go ahead and pull up our slack, and then we'll go ahead and add a ring terminal to the other end. Now we're going to attach this to the clamp that goes directly to the battery terminal. Now the ring terminal itself is on the large side, so we're going to use a couple of extra washers to help get a good grip on the ring terminal. We'll go ahead and take a washer, put it on first, then our ring terminal, another washer, and then our nut. The part number for the nut we're using is 185916. We'll go ahead and tighten it down, and then snap the cover back into place. Everything's installed. We'll go ahead and try it out with a test light before we try it on our trailer. We'll take our ground from our test light and connect it to the white wire. Then we'll test our brown wire for our running light circuit. And then our yellow wire will be our left turn signal, and our green will be our right turn signal. Now our brake signal will be a constant signal on the yellow and green wires. Looks like everything works. Now when we need t use it, we'll go ahead and simply pull it out and shut the hatch on it. The door seal is thick enough where it won't hurt the wire harness. But you do want to stay away from the latch in the center, because that will cause a short once the wires are smashed together. When the wire harness is not needed, we'll simply store it with the spare tire. And that will finish it for our install of part number 118501 from Tow Ready, on our 2012 Hyundai Tucson. .

Info for this part was:

Employee Joe V
Test Fit:
Joe V
Employee Shane T
Test Fit:
Shane T
Employee Andrew S
Test Fit:
Andrew S
Employee Shane H
Test Fit:
Shane H
Employee Clayton O
Test Fit:
Clayton O
Employee Andrew K
Video by:
Andrew K
Employee Kathleen M
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Kathleen M
Employee Jonathan Y
Video by:
Jonathan Y
Employee Joshua S
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Joshua S
Employee Dustin K
Video Edited:
Dustin K
Employee Chris R
Video Edited:
Chris R
Employee Cole B
Installed by:
Cole B

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