T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Item # 118786

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Custom Fit Vehicle Wiring

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118786 - Powered Converter Tekonsha Custom Fit Vehicle Wiring
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Product Images

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  • Custom Fit
  • Trailer Hitch Wiring
  • Tekonsha
  • 4 Flat
  • Powered Converter
Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered ModuLite reduces strain on wiring system. Call 800-298-8924 to order Tekonsha custom fit vehicle wiring part number 118786 or order online at etrailer.com. Free expert support on all Tekonsha products. Guaranteed Lowest Price and Fastest Shipping for T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.


  • All Info
  • Reviews (40)
  • Q & A (55)
  • Videos (3)
  • Photos
  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring - 118786

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered ModuLite reduces strain on wiring system.


Features:

  • Provides a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Connects quickly and easily
    • Locate connection points behind tail lights
    • Plug in T-connector
    • Run hot lead to car battery
  • Includes ModuLite power module that connects directly to battery to avoid overloading vehicle's electrical system
  • Constructed of 16-gauge bonded wire
  • Comes with dust cap for 4-way flat connector


Specs:

  • Maximum amperage:
    • Stop/turn lights: 5 amps per circuit
    • Tail lights: 7.5 amps per circuit
  • 1-Year limited warranty


Installation

This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located behind the driver's-side and passenger's-side tail lights. You will have to remove the access cover and the tail light assemblies to access this harness.


T-One Connection Location Points Behind Tail Lights

Once you've plugged in the T-connector, run the hot lead up to your car battery. Connect the lead to the included fuse holder, and then connect the fuse holder to the positive terminal on your battery and insert the provided fuse.


Once installation is complete, the 4-way flat connector will be stowed beneath your vehicle. A mounting bracket (sold separately) is recommended to keep the connector secure.


It is recommended that you use a small amount of grease on all electrical connections - the plugs on your automobile and the 4-pole connector itself - to help prevent corrosion.


ModuLite Power Module

A ModuLite power module is built into this T-One connector. With a ModuLite, your trailer's lights will be powered without overloading your vehicle's electrical system. Because the module draws power directly from your car's battery and bypasses the electrical routes that are used by a basic wiring harness, there is virtually no draw on your tail light circuits.



118786 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite

Replaces Tekonsha 118782



118786 Installation InstructionsInstallation Details 118786 Installation instructions

This Product Fits The Following Vehicles

2020 - 2020 Jeep Gladiator

2018 - 2018 Jeep JL Wrangler

2018 - 2018 Jeep JL Wrangler Unlimited

2019 - 2020 Jeep Wrangler

2019 - 2020 Jeep Wrangler Unlimited

2018 - 2018 Jeep JL Wrangler without factory Tow Package

2018 - 2018 Jeep JL Wrangler Unlimited without factory Tow Package

2019 - 2020 Jeep Wrangler without factory Tow Package

2019 - 2020 Jeep Wrangler Unlimited without factory Tow Package



California residents: click here


Video of T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector


Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Tekonsha T-One Vehicle Wiring Harness Installation - 2018 Jeep JL Wrangler Unlimited

Today on our 2018 Jeep JL Wrangler Unlimited you're going to be taking a look at, I'm going to show you how to install the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. This is what our wiring looks like when it's installed. This is going to be used for all of the proper lighting functions to safely tow a trailer: both turn signals, brake lights, running lights, and your ground. It's also going to come with a nice dust cap to help keep any dirt and debris from your connections.What's nice about the Tekonsha, it's going to come with a converter box. It's going to protect your factory wiring from any back feed from your trailer, and vice versa, protect your wiring from your trailer from any back feed from your factory wiring on your vehicle. As far as the installation goes, it's pretty simple and straightforward.

It's going to be a plug and place, so it's going to plug directly into your factory wire. You're just going to have a power wire that you're going to route to the front up to the battery.First thing we need to do to start our installation, we're going to get in the back of the vehicle. We need to remove our taillights. When you come right inside, there's a little cap on each side. Take a screwdriver, a flathead screwdriver, a plastic trim panel tool if you have one, and we're going to pop this cap off.

Right inside we're going to have a plastic nut. We'll use a 10 millimeter socket. We're going to remove that nut.We're going to slide our taillight straight to the back like that. Our connector, we're going to have a red tab. Pull up on the tab.

We're going to push down on this black part here. Push down, separate your plug. Then you're going to repeat that same process for the passenger side. Next we're going to take our power wire, and you're going to have a large hole down underneath your taillight houser and in your taillight housing on your driver side.To pass your wire down or up, you can do either way. I'm going to come up through it, so I don't have to worry about all this wire, trying to get it down through there.

So, you can see where the hole is. The gas tank filler neck goes down through there. I'm going to take my 4-pole wire, or the end. I'm going to go down through that hole, come out of the bottom of the vehicle. Then I'm going to do the same thing with my green wire. I'm going to take my black wire that I fed through first, strip back the end, add on a heat shrink butt connector.Then we're going to take the black wire on our wiring harness. We're going to put it in the other end. Then take a heat source and shrink the butt connector. Next we're going to mount our ground wire. Self-tapping screw, it comes in your kit, 1/4 inch socket. This edge right here, as long as it's on metal, the ground will work. This edge right here is the perfect place to put it. Just like that. We're going to take an alcohol pad, rubbing alcohol and paper towel, whatever.We're going to clean an area to mount our converter box. I'm going to mount mine right down on the bottom down here because it's flat. You just want to make sure that the area is good and clean so the double-sided tape that comes in your kit sticks well. Push on it good to make sure everything is held in place well. Now I'm just going to match my two ends on my plug. Before I make the connection, I suggest putting some dielectric grease on the insides of your plugs. It helps prevent moisture building up and corrosion. If you don't have any dielectric grease, you can find it here at etrailer.com.Don't forget your red tab, and then we can reinstall our taillight. Next we need to run our green wire over to our passenger side. We need to make sure any wires we run, we stay away from any heat or moving parts. What I did is I went over top of my frame rail. There's two nuts on the edge of your heat shield, 9/16 socket. Pull those off. Pull down your heat shield just a little bit, and I ran my green wire right underneath of it. I just reinstalled my two nuts. That keeps my wire up away from my muffler.Went over top my frame rail same place here, and then we're going to have the same pocket here on the passenger side as we did on the driver. You just reach up. You can set your wiring right up inside that pocket. Here's my passenger side green wire. The pocket is back in there. The difference between the passenger and driver side is we got to go through this little hole. You've just got to reach your finger back there and pull your wiring harness through it. Other than that, your connections are going to be the same as you did on the driver side.Now we need to run our power wire up to the front of the vehicle. Because our wiring came down over here, we had to get it over to the passenger side because that's where our battery is. We need to make sure we stay away from anything hot or moving. Went over top of my frame rail, the same way I did my green wire, except when we got on this back side, we have our muffler pipe, our exhaust pipe that runs up over top of our axle. What I did is I went overtop of my heat shield, and this is where I crossed over the passenger side.Went right on top of my frame. I zip tied it to this factory wiring here, right along the top, right here to the front. We have some existing wiring. I went behind this factory ground here, and then from the top side, you got two ways of doing this. I have some airline tube to drop it down. If you don't have airline tube, another easy way to do it is take a piece of string with a nut. Because it's a Jeep, it has a lot of room here, so you can drop that nut down to give you something weighted or something to tie your extra wire onto to pull it up into the engine compartment up by your battery.I actually ran it right underneath of this wire here, this ground wire, up underneath. I actually zip tied it there to make sure it stays up tight. Now what we're going to do is I'm going to take my fuse holder. We're going to cut it in half. I'm going to strip both ends. One end, we'll add a ring terminal. The other end, we'll add a heat shrink butt connector. Now we're going to take our wire. We'll cut it down to size. I'm going to cut it about here, because then my fuse holder will hang down. I can store it over to the side here. That end.Then put that into the other end of your butt connector. Then we'll take our heat source and shrink that up. Take a 12 millimeter socket. I removed this nut here. We'll go ahead and add a ring terminal to replace the nut. You're going to make sure when you make this connection, your fuse is not in the holder. Then we can go ahead and add our fuse once the connection is made. Now, to give my 4-pole wire or plug a more permanent location, I used a no-drill mounting bracket and a 4-pole bracket.With the no-drill mounting bracket, the long bracket, I actually had to bend it into a square to go around my frame rail. My 4-pole bracket attaches right to the bottom. You can see how I have it. My wiring, I came through the outside of my frame away from my exhaust. Bundled it up, zip tied it, and then zip tied it to my frame rail. Now we'll test out our wiring using part number 126. Left turn, right turn, brake lights, running lights. That'll do it for a look at and installation on our Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector on our 2018 Jeep JL Wrangler Unlimited.


Customer Reviews

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 118786

Average Customer Rating:  5.0 out of 5 stars   (40 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered ModuLite reduces strain on wiring system.

- 118786
by:
2018 Jeep JL Wrangler

shipping was fast in just over 24 hours. wiring was packaged neatly and was blemish free. wiring harness works great. install was a bit challenging as I ran my power cord through the frame tubing as per the etrailer videos. enclosed instructions are useless. if I was etrailer I would provide more protection for the green wire going over to the passenger side like an additional protective sleeve. the green wire is just draped over the heat shield with no additional protection. hopefully ill have years of problem free usage out of the wiring harness. I also purchased the angle bracket to install the 4 way on to the hitch. etrailer should supply hardware for this application also. 606850



- 118786
by:

very easy install thanks to the outstanding video. Adding this and an $80 -2 inch receiver was way cheaper than buying from the dealer. Since I had the taillights off, i threw in a fuel filler door at the same time. 619590



- 118786
by:
Jeep

Excellent product, great directions, quality materials and works perfectly! etrailer processed and shipped the order quickly and delivery was on time as usual. All wiring, harnesses and connectors are high quality, perfect fit for my 2019 Jeep JLU. Ran power to battery, installed all other hardware per directions, inserted the inline fuse and WAHLA.... trailer running lights, blinkers, hazards and brake lights work like a charm! I highly recommend etrailer and this product. 607885



- 118786
by:

All the components installed and works just like the instruction video. 619842



- 118786
by:
2018 Jeep JL Wrangler

Product looks great, will follow up once completely installed. 556143



- 118786
by:
2018 Jeep JL Wrangler Unlimited

Great product - as advertised. 521140



- 118786
by:
2018 Jeep Wrangler

I've purchased a handful of trailer hitches/wiring harnesses over the past 10 years and they have always been awesome!! Quality products and fast shipping every time!! Just recieved a new class 111 hitch & wiring harness for my 2018 Wrangler JL and installed the hitch in less then 10 minutes and the wiring was approximately an hour after watching the video provided on their website. Never been disappointed!! 640253



- 118786
by:

I haven’t put in in yet, but it looks like it is exact the item I need. Price was $140 cheeped than I found in other paces. 570274



- 118786
by:
2018 Jeep Wrangler

I received the trailer hitch wiring kit very quickly and installed it with no issues. I have a 2018 Wrangler Sahara JL. I saw in the questions section on eTrailer that some people had issues in the Sahara and Rubicon models due to the tail light connectors being different but it went right in with no problems. I highly recommend the use of a lift if you have access to one. Being able to stand under the car made everything much easier. 609325



- 118786
by:
2018 Jeep JL Wrangler Unlimited

Received my wiring harness when it was promised and installed in about an hour. Everything worked perfectly. 543330



- 118786
by:
2018 Jeep JL Wrangler Unlimited

I can't say how great it was to talk to the folks at etrailer.com. Their help and guidance was spot on. The order shipped same day and arrived as expected. Best of all everything fit and was working on the first hookup. And more importantly it gave me peace of mind knowing the wiring works and will continue to work for years to come. Thanks much! 519064



- 118786
by:
2018 Jeep JL Wrangler

Product was very good quality. Directions are clear and well done. Connectors fit nicely. Took on the order of 4 hours to complete largely because you need to run a hot wire to the battery and it took some time to find a good routing. I also solder all connections and use shrink wrap over the connections so this took some time as well. I think it is a very good product. The team at etrailer was great as well. 499436



- 118786
by:
2018 Jeep Wrangler

My Jeep is a 2018 Wrangler Unlimited JL Sport S with the standard halogen headlights and not the LED upgrade. I wired this T-One kit up in about 4 hours. I have pretty good mechanical knowledge and I'd say this kit is something that would be intimidating for someone who's never done it before. I ended up using a large part of the tools in my garage including a drill, various bits, a stick magnet (dropped the ground screw down into a cavity on the Jeep and couldn't find it), 1/4" ratchet, long extension, various sockets, flashlight, pliers, trim tool, wire crimp tool, lighter, T40 torx socket, extra zip ties, flat blade screw driver, etc. I used the grommet on the firewall behind the brake booster to run the power wire from the battery into the cabin of the Jeep. Tucked the power wire under the door sill trimwork all the way to the rear. Had to disassemble a large part of the trimwork at the rear of the Jeep to access the grommet that goes down into the driver side tail light. Then I was able to do my connections inside the cavity for the tail light, mount the converter box in there, and route the 4-pin and passenger side T-connector out the back of the cavity near the fuel filler tube. From there, across the top of the crossmember, and up into the passenger side tail light from the bottom. To do the install properly, it took a while and a good assortment of tools and a little knowledge of how plastic trim panels are attached so that you can remove them without breaking them. If you're not comfortable disassembling your new Jeep, order the factory tow package!! But if you want to save $650, order the hitch and wiring here at this site and do it yourself on a Saturday. Installation was a pain, but the kit included everything I needed (except the assortment of tools) and was well made. Trailer lights all work as expected. Hopefully the wiring will give me years of service. 502313


Comments

Still works great a year later. Did need to apply dielectric grease to the pins on the trailer connector but all seems well.

Shawn - 04/29/2019

54619

- 118786
by:

Excellent Product, Delivery Time, and Customer Service. Most definitely will order more from Etrailer!!! 569102



- 118786
by:
2018 Jeep JL Wrangler

Wiring harness for Jeep JL appears well constructed. Phoned tech line with some unusual questions. Spoke to Dianna who answer most Q. immediately,those others she found out for me. Thx.! Curt trailer hitch instructions stated a 20 min install time , historically this never happens. This time the install time was right on. Good quality hitch ,well made and everything fit perfectly. 596421



- 118786
by:
2019 Jeep Wrangler Unlimited

etrailer, great people to work with. Trailer hitch and wiring harness worked perfectly. The video demonstrating the wiring harness installation was spot on. Plenty of wire length, nothing to wish for. Thank you again for my second hitch install. 715065



- 118786
by:
Honda Pilot

Ordered part on Sunday night and delivered and installed on Wednesday night. Easy install and only thing I did different was to drill a small pilot hole for ground attachment behind driver side tail light. 707685



- 118786
by:

the wiring work and still working good, job well done by your employees, I had no problems with it. 704740



- 118786
by:
2019 Jeep Wrangler

The video was very helpful in installation. There were a few time reality was a bit more difficult than the video suggested. Good product at reasonable cost. 698959



- 118786
by:
2018 Jeep JL Wrangler

My husband and I recently bought a new Jeep Wrangler JL. The Jeep dealership offered to install trailer lights and a new hitch for "their cost" of over $900. YIKES! Then, we contacted a local business that said they could do it for $400 to $500, but they couldn't get to it for a few weeks. Still kind of steep. My husband didn't want to wait that long and was ready to get a hitch installed so he could go fishing. So he watched a few DIY videos and decided to try it himself. That's how we learned about the wiring kit from etrailer. According to the guys in the videos (they were not affiliated with etrailer), it was going to take a day or two to get it all installed. They kind of acted like it was a chore that required lots of bandages for cuts on their hands, but my husband was up for the challenge and the pain. Those yahoos from [the video] obviously didn't know what they were doing. They made it a lot harder than it really was. It only took my husband a couple of hours to get it all wired up, hitch installed and done lickity split. He did it all pain free and didn't need a single bandage. He said that it was ridiculously easy to install. And we are so excited about all the money we saved by doing it ourselves!! Thank you, etrailer, for your quality products and amazingly affordable prices!! 680140



- 118786
by:
Jeep

Great product! Took about 1 hour to install. Used video for help. Put on 2018 Jeep JL Unlimited. 670136



- 118786
by:

Very easy install! Big savings versus having the dealer do it! Good instructions easy to follow 669682



- 118786
by:
2019 Jeep Wrangler

I watched the install video. installation was easy. took about an hour. Works great. Transaction = faultless. 665437



- 118786
by:
2018 Jeep JL Wrangler Unlimited

Easy to install and works fine! 652946



- 118786
by:
2018 Jeep JL Wrangler Unlimited

Perfect product for my needs ( 2018 JLU 4 door ). The installation video provided was a Godsend ! Took my laptop out in the garage and went step by step to get a perfect job. The toughest part ( not really that tough ) was running the power wire up over the frame rail to the battery. Tail lights were plug and play so you can't get that wrong even if you try. Everything needed for the install including small wire ties to hold everything together. 617596



- 118786
by:

will let you know how the instal goes 616325



- 118786
by:
2018 Jeep JL Wrangler

Wiring harness was very easy to install. Nice product and works perfect so far. Shipping was very fast. 613808



- 118786
by:

Excellent Product, easy to install!! 613504



- 118786
by:
2018 Jeep JL Wrangler

Easy to install and fits perfect. 609308



- 118786
by:
2018 Jeep JL Wrangler

As always, etrailer delivered again! 606715



- 118786
by:

Easy to install. 598877



- 118786
by:

Easy to install and works well. 596008



- 118786
by:
2018 Jeep JL Wrangler Unlimited

the hitch is well made and heavy duty. The wiring harness looks first rate and should be simple to install. 595003



- 118786
by:
2018 Jeep JL Wrangler

Great service. Awesome rep. 594085



- 118786
by:
2018 Jeep Wrangler

Great fit for my Rubicon JL!! 585578



- 118786
by:
2018 Jeep JL Wrangler Unlimited

Product arrived on time and is good quality. Installed in an hour and works great. 562712



- 118786
by:
2018 Jeep JL Wrangler Unlimited

Works as advertised. The Directions were good, easy to follow. 557972



- 118786
by:

On time and great product!! 556137



- 118786
by:
2018 Jeep JL Wrangler Unlimited

Straight forward easy install. 550343



- 118786
by:
2018 Jeep JL Wrangler

Absolutely satisfied. Top quality comp onents. 513816


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Ask the Experts about this Tekonsha Custom Fit Vehicle Wiring

Do you have a question about this Custom Fit Vehicle Wiring?


  • Flat Towing Wiring Kit for a 2018 Jeep JL Wrangler Unlimited
  • The Tekonsha T-One # 118786 that you referenced is for activating the light functions on a trailer when towing with your 2018 Jeep JL Wrangler Unlimited. It sounds like you are needing some wiring to flat tow your Jeep and for that you need some different parts. If you use the Hy-Power Diode Wiring Kit # RM-152 along with the Hopkins Mounting Bracket # HM48605 and the Pollak Heavy-Duty, 4-Pole, Round Pin Socket # PK11410 then you will essentially have the Flexo-Coil Wiring Kit # RM-15267...
    view full answer...

  • Best 4-Way Trailer Wiring Kit Recommendation for 2018 Jeep JL Wrangler
  • The best choice for 4-way trailer wiring for your 2018 Jeep Wrangler JL is the T-One kit part # 118786. Reason is it has higher amperage ratings so it would be more difficult to short out and because T-One in general just makes more reliable trailer wiring for vehicles.
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  • Brake Controller and 7-Way Recommendation for 2019 Jeep Wrangler Unlimited
  • To install a 7-way and brake controller in your 2019 Jeep Wrangler Unlimited first requires you to install a 4-way connector part # 118786 which provides all of the trailer lighting functions and then convert to a 7-way with the part # ETBC7 which the 4-way plugs into and comes with everything needed to wire up a brake controller. I attached an install video for this kit on a similar 2012 Jeep Wrangler Unlimited as yours for you to check out as well. For a brake controller I would recommend...
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  • Recommended Trailer Hitch And Wiring for a 2019 Jeep Wrangler
  • For your 2019 Jeep Wrangler, I recommend the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # 118786 which is a plug and play kit that does not require any splicing. I have attached an install video for you as well on a similar 2018 model if you need help. If you have not yet picked out a trailer hitch, I recommend going with the Draw-Tite Max-Frame Trailer Hitch Receiver part # 76104 because it offers the most capacity and the receiver tube opening is less recessed...
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  • Trailer Wiring Recommendation for 2018 Jeep Wrangler JL Unlimited
  • For your 2018 Jeep Wrangler JL Unlimited the T-One trailer wiring kit part # 118786 is a confirmed fit and would be what we recommend. This is our most reliable brand of trailer wiring so it's the way to go. Now if your trailer does not have brakes all you would need is the part # 37185 as an adapter to convert the 4-way to a 7-way. If you do have trailer brakes you would need the # ETBC7 instead of the # 37185 and a brake controller. This kit comes with everything needed to wire...
    view full answer...

  • Recommended Trailer Hitch for 2018 Jeep Wrangler Unlimited
  • For your 2018 Jeep Wrangler Unlimited I recommend Trailer Hitch # e98856, which is a confirmed fit for the JL Unlimited like your Sahara. This is a complete bolt-on installation and nothing will need to be removed unless there are any obstructions such as excess welding on the crossmember where it installs For wiring which will give your Jeep a 4-way connector and allow you to power your trailer's lights you need Wiring Harness # 118786. I also recommend checking out Ball Mount Kit...
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  • Trailer Wiring Harness for a 2018 Jeep Wrangler Unlimited JL
  • You are correct, they are different shapes. The JL is the newest generation of the Jeep Wrangler. But there are also some 2018 JK models. Luckily we have them separated out in our fit guide. For your 2018 JL model you will need wiring harness # 118786. This is a brand new harness designed especially for the JL models. I can assure you that this will have the correct connectors for your Jeep.
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  • Recommended 4-Way Wiring Harness for 2018 Jeep Wrangler JL
  • The Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118786 is a confirmed fit for your 2018 Jeep Wrangler JL. I recommend this kit over the harness # 119147KIT which will also work, but requires splicing instead of using the factory wiring harness quick connects located behind the driver's and passenger's side tail lights.
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  • Installing a Brake Controller on a 2018 Jeep JL Wrangler Unlimited with Factory Tow Package
  • While I cannot confirm a brake controller wiring harness for the 2018 Jeep JL Wrangler Unlimited there is still a way to install a brake controller. First you would need a 4-Way wiring harness. We do have trailer wiring harnesses for the 2018 Jeep JL Wrangler Unlimited. For models without the factory tow package Curt has # C56407 and Tekonsha has # 118786. There is a note on the Tekonsha harness though that states it does not currently work with Rubicon or Sahara models. Adding a...
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  • Prodigy P3 Brake Controller Installation in 2018 Jeep JL Wrangler without Tow Package
  • Brake controllers like the excellent Prodigy P3 # 90195 use the vehicle brake light switch to deliver the electrical signal that tells the controller your vehicle is braking, and from there the built-in accelerometer sensor determines the amount of braking power that needs to be sent to the trailer's brakes. This is how all proportional type brake controllers operate. They take in the triggering electrical signal from the pedal and then proportionally deliver brake power to match the rate...
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  • Why Does Trailer Wiring 2018 Jeep Wrangler JL Need to Run Directly to Vehicle Battery
  • Not all vehicles can handle the additional amperage draw of the trailer taillights on the vehicle taillight circuits. Those vehicles need setup that draws power from the battery. Some vehicles have higher rated circuits that can handle this, and others need to have the power drawn straight from the battery to protect the taillight circuits. While it seems easier to just run the power wire to an available accessory circuit it's not the best idea to go that route. In the event of a short...
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  • Will T-One Vehicle Wiring Harness fit 2018 Jeep JL Wrangler Sport S with LED Lights
  • Yes, the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118786 is perfectly compatible with LED lights. This harness is a fit and work great on a 2018 Jeep JL Wrangler Sport S without the factory tow package. I have added a link to an installation video of this part for you to check out as well.
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  • Wiring Options for a Brake Controller on a 2018 Jeep JL Wrangler Unlimited Without Tow Package
  • Since your 2018 Jeep JL Wrangler Unlimited doesn't have the factory tow package you will need to start off with 4-Way wiring like the recommended Tekonsha T-One # 118786. Once you have that installed there are a few options for you. You can either install the 7-Way RV Upgrade Kit # ETBC7L which only adds 12V power to the 7-Way and allows you to use the Curt Echo # C51180 brake controller with an Apple or Android smart device, or you can install the Universal Installation Kit # ETBC7...
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  • 2018 Wrangler JL 5-Way Trailer Wiring Harness
  • We certainly do. The solution is basically to convert a 4-way to a 5-way. If your 2018 Jeep JL already has a 4-way then you simply need to convert it. If it doesn't already have any trailer wiring then you need to start with a custom 4-way harness. The Tekonsha, part # 118786, has the highest maximum amperage available for the wiring that fits your Jeep so it's what I'd choose. It plugs inline behind both tail lights and then has a hot lead that's run to the Jeep's battery. I've...
    view full answer...

  • Recommended Brake Controller and Wiring for 2018 Jeep Wrangler JL
  • Absolutely. If your 2018 Jeep Wrangler JL has the 7-way installed, then you will use Wiring Kit # 5506. If your vehicle doesn't have trailer wiring, then you can use the Universal Brake Controller Wiring Kit # ETBC7. This kit comes with everything you need to connect to a 4-way wiring harness. If you don't have that yet, then I recommend the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118786. This will install behind the tail lights and draw power directly from...
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  • Will Installing Trailer Wiring Harness Void Warranty on 2019 Jeep Wrangler
  • That is a great question. The good news is that consumers are protected by the Federal Magnuson-Moss Warranty Act. This act essentially states that if something were to break or go wrong on your Jeep and you take it in for warranty repair, the dealer must honor the warranty regardless of what modifications have been made unless the modification is what caused the issue. Installing an aftermarket wiring harness like the excellent Tekonsha T-One # 118786 yourself that you referenced will...
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  • Recommended Trailer Hitch Receiver for 2018 Jeep Wrangler Unlimited JK and JL Models
  • All of the JL Wrangler Unlimited hitches we carry will work on the JK Wrangler Unlimited models, but there are some JK model hitches that are not compatible with the JL Wranglers based on fit guide from the manufacturer because they have a shorter receiver. The bolt mounting holes are in the exact same location. Unless you are doing rock crawling, I recommend getting the longer receiver like the # e98856 or Curt # C13392 which will allow more accessories such as bike racks and cargo...
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  • Trailer Hitch, 7-Way, and Brake Controller Recommendation for 2018 Jeep JL Wrangler Unlimited
  • For your 2018 Jeep Wrangler JL Unlimited the Draw Tite part # 76104 is a confirmed fit and would be an excellent option. For trailer wiring you'd need to start with a 4-way and then convert it to a 7 and 4-way. For that you'd need the part # 118786. Now if your trailer does not have brakes all you would need is the part # 37185 as an adapter to convert the 4-way to a 7-way. It also leaves you with a 4-way on the side of the socket as well. If you do have trailer brakes you would...
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  • Best Trailer Wiring Harness for a 2018 Jeep JL Wrangler Sahara
  • Yes, the T-One Vehicle Wiring Harness part # 118786 which replaced the T-One Vehicle Wiring Harness part 118782 is now compatible with Sahara and Rubicon editions of the 2018 Jeep JL Wrangler.
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  • Recommended Trailer Hitch Receiver for 2018 Jeep Wrangler JL Unlimited Sahara
  • For a similar trailer hitch receiver, I recommend the Curt Trailer Hitch Receiver # C13392. This is a confirmed fit for 2018 to present JL Wranglers. The Curt Trailer Hitch Receiver # 9883544 is a fit for the 2018 JK Wrangler models only. If you need trailer wiring, I recommend the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118786. This custom-fit T-One connector plugs into your Jeep JL Wrangler Unlimited's wiring harness, which is located behind...
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  • Trailer Wiring Harness Recommendation for 2018 Jeep Wrangler JL
  • The trailer wiring harness I recommend for your 2018 Jeep JL Wrangler 4-cylinder is the Tekonsha kit part # 118786 that you referenced. This is a custom fit harness which means it will install easily and it comes with a very reliable converter box so it will last a long time too. I attached an install video for this kit on a 2018 JL just like yours for you to check out as well.
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  • 2018 Jeep Wrangler JL Unlimited 4-Way Trailer Wiring Harness
  • For your 2018 Jeep JL Wrangler Unlimited the correct trailer wiring harness is the Tekonsha part # 118786 which is a confirmed fit. This installs by plugging inline with the taillight wiring of your Jeep to operate the trailer wiring. Of the trailer wiring brands on the market the Tekonsha brand is the most reliable.
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  • 2018 Jeep Wrangler Unlimited Rubicon Trailer Wiring Harness Recommendation
  • For your 2018 Jeep Wrangler Unlimited JL Rubicon the T-One 4-way harness part # 118786 is a confirmed fit that will not cause any dash lights to come on. This would be a great solution. This is our most reliable trailer wiring brand so we recommend it the highest. It installs by plugging inline with your taillight assemblies which allows it to function without the vehicle wiring even knowing it's there.
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  • Custom Fit Trailer Wiring Harness Recommendation for 2018 Jeep JL Wrangler
  • For the 2018 Jeep Wrangler JL that you have we have the Tekonsha 4-way kit part # 118786 which is a confirmed custom fit and would work well. This installs by plugging inline with the tailight harnesses of your Jeep as you can see in the install instructions I attached below.
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  • Troubleshooting No Running Lights After Installing Tekonsha Harness on 2018 Jeep JL Wrangler
  • There are a couple possible reasons as to why the running lights are not working after installing the Tekonsha T-One Vehicle Wiring Harness # 118786 on your 2018 Jeep Wrangler JL Unlimited. First, since this harness does require that a hot lead be run up to the vehicle's battery, I recommend making sure all the connections under the hood are secure. Since the Jeep's battery is what will actually be powering the harness, you will want to ensure that the black power wire from the T-Connector...
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  • Does Trailer Wiring Harness have to Connect to Battery on a 2018 Jeep JL Wrangler
  • There are several reasons why the power wire has to connect directly to the vehicle battery when installing trailer wiring harness # 118786 on your 2018 Jeep JL Wrangler. First, the 12 volt accessory circuit was not designed to support the additional power draw of the trailer wiring harness. A wiring harness must have its own dedicated fused connection to the battery. Second, attaching the power wire to the battery maintains the level of separation between the vehicle wiring and...
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  • Does Trailer Wiring for 2018 Jeep Wrangler JL Unlimited Have to Run to Battery Post
  • Not all vehicles can handle the additional amperage draw of the trailer taillights on the vehicle taillight circuits. Those vehicles need setup that draws power from the battery. Some vehicles have higher rated circuits that can handle this, and others need to have the power drawn straight from the battery to protect the taillight circuits. For your 2018 Jeep Wrangler Unlimited JL you need to install a harness that draws power from the battery to protect the taillight circuits. For that...
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  • Trailer Wiring Recommendation for 2019 Jeep Wrangler JL
  • We have a confirmed fit for custom trailer wiring for your 2019 Jeep Wrangler JL as part # 118786 that we know will fit and work well. We can't really tell you if our competitors are up on the most current fit info though.
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  • Will Trailer Wiring Harness 118786 Work on a 2018 Jeep JL Wrangler Unlimited with LED Tail Lights
  • I checked with Tekonsha, the manufacturer of wiring harness # 118786, and there are no known issues with this wiring harness and LED lights on the new 2018 Jeep JL Wrangler Unlimited.
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  • Trailer Wiring Harness for a 2018 Jeep JL Wrangler Unlimited Sahara
  • Apparently the 2018 Jeep JL Wrangler Unlimited Sahara and Rubicon models have a different type of tail light and the connectors on old wiring harness 118782 do not match up. In order to add a trailer connector on those models or other JL models you will need to use # 118786.
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Info for this part was:

Edited by:
Lindsey S
Expert Research:
Jameson C
Expert Research:
Adam R
Video Edited:
Dustin K
Video Edited:
Chris R
Installed by:
Cole B
Updated by:
Alexander C
Updated by:
Isabelle B
Written by:
Ronnie R
Test Fit:
Shane H
Video by:
Michael B

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