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  1. Custom Fit Vehicle Wiring
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  3. Custom Fit
  4. Trailer Hitch Wiring
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T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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

Item # 118786
Retail:$116.61
Our Price: $85.47
You Save: 27%
Custom Fit Vehicle Wiring

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Shipping Weight: 1.85 lbs
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Tekonsha Custom Fit Vehicle Wiring - 118786
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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. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number 118786 or order online at etrailer.com. Free expert support on all Tekonsha products. Great prices and Fastest Shipping for T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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  • Reviews (253)
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Tekonsha Custom Fit Vehicle Wiring - 118786

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • Powered Converter
  • Tekonsha

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

Installation Details 118786 Installation instructions

This Product Fits The Following Vehicles



California residents: click here


Customer Satisfaction Score:


Customer Reviews

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

Average Customer Rating:  4.9 out of 5 stars   (253 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.

by:

Easy to install, hot wire attached to lug on side of fuse block w/fuse.
Use 4' flex rod for electrical to fish wire to fuse block under vehicle



by:

Another successful order and install from etrailer.com! Always fast shipping and excellent installation guide videos! Installed on 2021 JL Wrangler EcoDiesel.



by:
2021 Jeep Wrangler Unlimited

I am not one to work on my vehicles, mostly because I find it to be of very little interest.” Unfortunately,” with the economy heading south and prices soaring “ AGAIN “, I found myself in a sqeeze.
I put on my big boys work wear nand attacked the installation of the wiring harness kit for My 2021 Wrangler 80th anniversary Jeep.
The directions were very easy to follow and before I knew it, I was wrapping it up. Start to finish in one hour and forty five minutes. Thank you etrailer



by:

Jeeps are notorious for electrical problems. This product isolates the automotive system from a trailers systems. Very good idea and I love it. My background is in aircraft electrical systems. I have worked in this field since 1977. This is a great product. I'll buy another if needed and I'll recommend it to others.



by:

I looked at a lot of auto stores . No one could come up with what I needed.
Contacted etrailer. Problem solved.
Thank you, etrailer!



by:

Perfect package - comes with everything you need and good instructions. I found a video on the etrailers site was more helpful than the printed ones.



by:

Wiring working excellent on my 23 Jeep Gladiator. Great company to deal with, you can't go wrong



by:
2018 Jeep JL Wrangler Unlimited

I prefer to use this Tekonsha module for the vehicle that don`t have the factory tow harness. The module was tucked away in the body cavity behind the drivers side tail lamp assy. All wiring was covered in HD split loom. All wiring was concealed as much as possible by running them through the cross rail and frame rail up to the battery positive terminal. I did lengthen the green wire on the passenger side to accomplish this. All connections were done with heat shrink connectors. Installation did take longer than usual based on the wire routing I chose. Overall I am totally satisfied with this product.



by:
2019 Jeep Wrangler

The harness came with great and simple instructions. I was easily to install it and it works great! Thanks for a great product and I highly recommend it for anyone looking to put a trailer harness on their vehicle.



by:

Fairly easy to install as long as the vehicle is up on ramps or even better would be a lift. I used ramps and crawled the length of my jeep to run the wires to the front and secured them to the frame away from heat or pinch points.



by:

Was easy to install, compatible with the factory plugs on my Jeep Wrangler. Aftre 1 year of use it’s woking god.



by:

Exactly what we wanted, hitch was very easy to put on. Very quick arrival. We ordered a wrong harness snd customer service was very quick and courteous to help us get a return label.
Would highly recommend this company.



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!!



by:

Product works well with my 2022 Jeep Wrangler 4xe. etrailer was great in helping to ensure that this product would actually work with my Jeep. Thank you!



by:

All good worked perfectly without a glitch. Towed the Jeep Wangler 4xe over 10,000 miles in 2023.



by:

Great harness that installed easily following video instructions.



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.



by:

The wiring harness was made of high quality parts and very easy to install. It had all the hardware need to wire it in correctly.



by:
2018 Jeep JL Wrangler Unlimited

everything looks great can't wait to install it



by:

Had exactly what I needed to wire my Jeep up for trailer lights. Very quality wiring harness and easy to follow instructions. They ship very fast and keep you updated on where your package is. Highly recommend etrailer!!!



by:

This wiring kit was just what I needed to get trailer light connection on my 2021 Jeep. I have been very satisfied with all of my purchases from etrailer!



by:

Simple. Assembly received complete. Works well.



by:

Customer service was excellent in getting exactly what we needed for first time installation. Thank you.



by:

Easy install!



by:
2020 Jeep Wrangler

Very easy install. Etrailer was very easy to deal with. Very quick shipping!!!!


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Show More Reviews

See what our Experts say about this Tekonsha Custom Fit Vehicle Wiring

  • Trailer Wiring Harness for 2022 Jeep Wrangler 4xe
    The Tekonsha # 118786 is indeed a confirmed fit for your 2022 Jeep Wrangler 4xe. I've personally confirmed this with my contact in the Technical Services department at Tekonsha who tells me that the harness is a fit for ALL models of the 2022 Jeep Wrangler JL. I've linked to an installation video that you might find helpful.
    view full answer...
  • 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.
    view full answer...
  • Best Trailer Wiring Harness for a 2018 Jeep JL Wrangler Rubicon
    Yes, the T-One Vehicle Wiring Harness part # 118786 will work on all 2018 Jeep JL Wranglers with factory LED and incandescent lights. This is actually an updated harness that was made to replace the T-One Vehicle Wiring Harness part 118782 that had issues with certain packages. There will be no issues whatsoever using the T-One Vehicle Wiring Harness part # 118786 on your 2018 Jeep JL Wrangler Rubicon.
    view full answer...
  • 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.
    view full answer...
  • Trailer Wiring For 2018 Jeep JL Wrangler
    The Roadmaster Universal HyPower diode wiring kit part # RM-154 is different wiring than what you need for towing a trailer with the 2018 Jeep Wrangler JL. You will need a 4-pole flat wiring harness part # 118786 which will plug in behind the Jeep's tail lights. You will plug the trailer connector on the trailer into the 4-pole to power the lights. I have attached an installation video for your reference.
    view full answer...
  • Is It Required To Run a Power Wire When Installing 4-Way Vehicle Wiring Harness 2023 Jeep Wrangler?
    Yes, you will have to run a power wire to your battery on your 2024 Jeep Wrangler Unlimited to have the 4-Way # 118786 function. This power wire provides power to the module as well as supplies the power for the wiring to the trailer. This protects the factory wiring from being overloaded and damaging your main harness.
    view full answer...
  • Troubleshooting Trailer Wiring of Jeep Where Only 12 Volt Accessory Circuit Works
    Typically this problem is caused by corrosion or dirt on the trailer wiring pins. I'd first try cleaning all of the pins of the 7-way with sandpaper and make sure none of them are bent or damaged. Other place to check is fuses under the hood of the vehicle if the wiring is OEM. You can also check to make sure the wiring behind the connector isn't damaged. I attached a link to a page that covers trailer wiring troubleshooting for you to check out as well.
    view full answer...
  • 4-Way For 2022 Jeep Wrangler 4xe With Flat Tow Wiring
    You can go from tow bar wiring to a 4-flat trailer connector on your 2022 Jeep Wrangler 4xe, as the two will simply plug in-line with one another, so no splicing is needed. So with your tow bar wiring all you need is the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118786.
    view full answer...
  • How to Install a Trailer Wiring Harness on a 2019 Jeep Wrangler
    Yes, the installation of a trailer wiring harness will be different for a 2019 Jeep Wrangler MOAB when compared to a 2013 Jeep Wrangler MOAB but not by much. Instead of just plugging in one connector behind the driver side tail light you will need to plug in a connector behind the passenger side tail light as well, run a power wire to the Jeep's battery, and ground the harness to a bare metal surface. For the above, I recommend using the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer...
    view full answer...
  • 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.
    view full answer...
  • 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.
    view full answer...
  • 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...
    view full answer...
  • Estimated Installation Time for Tekonsha 118786 Trailer Wiring Harness on 2019 Jeep Wrangler
    Tekonsha doesn't list an estimated installation time for their trailer wiring harnesses like they do with their trailer hitches, but after looking through the install instructions and viewing the linked installation video, I'd estimate that the install should take a professional about an hour, and a fairly capable do-it-yourselfer about an hour and a half. I'll also link to a help article that addresses how to run the wire from the rear of the vehicle up to the battery.
    view full answer...
  • No Power to 7-Way On A 2018 Jeep Wrangler
    Then it is possible that your 2018 Jeep Wrangler is not equipped with a trailer tow package. I did take a look at the owner's manual for the Jeep and F37 is the correct fuse placement if the Jeep is equipped according to the manual. Did you just install the 7-Way plug? If so, you may need to have the towing functions activated at the dealership. This is a fairly common issue.
    view full answer...
  • Recommended Wiring Harness for a 2022 Jeep Wrangler Unlimited 4xe
    I can confirm that the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector item # 118786 not only fits the Jeep Wrangler 4xe model but all models of the 2022 Jeep Wrangler JL. I've linked to an installation video below.
    view full answer...
  • No Power to 7-Way on a 2018 Jeep Wrangler JL
    Which pin are you testing on your 2018 Jeep Wrangler JL's 7-way? If it is the 12 volt power feed then you will need to check for a blown fuse. In the power distribution center (PDC) on your Jeep there will be a pink 30 amp fuse in the F37 slot that controls 12 volt power to the 7-way. If you are referring to the brake, stop/turn, or tail light pins then these will only show power while the circuit is active.
    view full answer...
  • Wiring Harness for a 2022 Jeep Wrangler
    Yes, there is a wiring harness that does not require cutting or splicing wires available for your 2022 Jeep Wrangler. It is the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector item # 118786. This custom-fit T-One connector plugs into your Jeep's wiring harness behind your rear tail lights. It plugs in-line without having to cut into the harness.
    view full answer...
  • Can Trailer Wiring be Run Under 2018 Jeep Wrangler JL
    You can absolutely run the 12 volt hot lead of the T-One Wiring Harness # 118786 under your 2018 Jeep Wrangler so long as you can find a way to route it to your battery. In fact, the linked directions state this as an option, which you can see by the accompanying cut out.
    view full answer...
    Image 1 for
  • 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...
    view full answer...
  • Trailer Wiring Harness Recommendation for 2018 Jeep Wrangler JL
    For your 2018 Jeep Wrangler Unlimited Sport with LED taillights the Tekonsha kit part # 118786 that you referenced is a confirmed fit and will work great. This kit has the highest amperage rating which means it will be the most resilient to wiring shorts and overdraws, and installs very easily so it's overall the best choice. I attached an install video for this on a similar 2018 Jeep Wrangler JL as yours for you to check out as well.
    view full answer...
  • 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.
    view full answer...
  • 4-way Connector for a 2022 Jeep Wrangler Unlimited
    Yes, the T-One Vehicle Wiring Harness # 118786 is a confirmed fit for your 2022 Jeep Wrangler Unlimited. This will provide you with a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights. If you are needing a ball mount you can pick up the etrailer Ball Mount Kit # 989900. This will provide you with 2 different ball mounts, 2 different hitch balls, 2 pin and clips and a storage bag.
    view full answer...
  • 4-Way Trailer Wiring Harness Recommendation for 2018 Jeep Wrangler Unlimited
    For trailer wiring the most reliable brand we offer is the Tekonsha brand by far so it's the brand I recommend the highest. So for that you'd want the # 118786 which is a confirmed fit for your 2018 Jeep JL Wrangler Unlimited and is compatible with the taillight style you have.
    view full answer...
  • Is Splicing Required to Install Trailer Wiring Harness 118786 on 2018 Jeep JL Wrangler Unlimited
    No, installation of trailer wiring harness # 118786 does not require splicing into the vehicle tail light wiring. It has connectors that plug in line with the tail light connectors on the 2018 Jeep Wrangler Unlimited JL models. A connection to the battery is required and will be what powers the trailer lights as well as part of what helps protect the Jeep's electrical system.
    view full answer...
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Info for this part was:

Employee Mike L
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Mike L
Employee Jameson C
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Jameson C
Employee Adam R
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Adam R
Employee Lindsey S
Edited by:
Lindsey S
Employee Joshua S
Video Edited:
Joshua S
Employee Jacob T
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Employee Dustin K
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Employee Chris R
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Employee Jonathan Y
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Employee Cole B
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Employee Isabelle B
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Employee Ronnie R
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