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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:$146.65
Our Price: $82.11
You Save: 44%
Custom Fit Vehicle Wiring

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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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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   (263 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

Mike

3/26/2024

Working great



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:
Roadmaster

On Sat 3/9/24 I called etrailer and attempted to order Roadmaster Direct-Connect Base plate.., phone lines down so you couldnt place my order. The price then was 397.71. You called me back following Sunday and was able to place my order. The price on same item one day after my first attempt was now $[XX] which I paid not reallizing the price had increased by $[XX] dollars . I checked your site and the price had indeed increased to $[XX]. I checked the site again on Tuesday 3/12/24 and the price had decreased again to $[XX]. I called you to have my account credited the $[XX] as I had not even received the item yet. You told me that couldnt be done. You would however re order and I could return the one that hadnt even arrived yet,, but that I would have to pay shipping of $[XX]. How ridiculous does this sound? You told me that if I paid for a gallon of gas one day and the price dropped the next day i couldnt expect the gas station to take it back so etrailer wouldnt credit me the $[XX] either. I can’t believe this happened even as I write this review it sounds so stupid. I feel I was over charged $[XX] and think I’m still due a credit. I have been a customer for years but no more.



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:
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:
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:

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



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:
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:

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:

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



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:

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:

Very fast and the items are excellent, Thanks



by:

Great company to deal with.



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:

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:
2022 Jeep Wrangler Unlimited

Easy to install, works perfect!



by:
2018 Jeep JL Wrangler Unlimited

everything looks great can't wait to install it



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:

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!!!


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Show More Reviews

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

  • 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...
    Image 1 for
  • 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...
  • 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...
  • 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...
  • 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...
  • Is The Tekonsha T-One Vehicle Wiring Harness # 118786 Made With Solid Copper Wire
    Hi Bob, No, most if not all trailer wire harnesses, including the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118786, are made of stranded copper wire. The wiring typically has to pass through tight areas and be able to easily bend so stranded wire is the easier and more cost effective option over solid wire.
    view full answer...
  • 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...
  • 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...
  • 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...
  • 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...
  • 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...
  • 4-Way Wiring Kit Recommendation for a 2021 Jeep Wrangler Unlimited
    For your application I recommend going with the T-One Wiring Kit # 118786. This tees in behind the tail lights on your 2021 Jeep Wrangler Unlimited and then you'll draw power directly from the wire that'll be ran up to your battery. This helps bypass your OEM wiring to prevent backfeed and overloading. This is as simple as it gets for your vehicle. Making the connections isn't too bad - the worst part really is running that power wire up to your battery. Just avoid hot and/or moving parts...
    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...
  • 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...
  • 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 the...
    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...
  • 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.
    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...
  • 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.
    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...
  • Troubleshooting Blown Fuse for T-One Trailer Wiring on a 2021 Jeep Wrangler
    Hey Mike! It sounds like you've got a wiring harness like the Tekonsha T-One # 118786 installed on your 2021 Jeep Wrangler. This uses a 15 amp fuse which may be why you're still blowing fuses since you're using 10 amps instead. Try using the 15 amp rated fuse and if that blows as well it means you have a bad ground connection somewhere, whether that's the ring terminal on the white wire (which needs to be connected to a clean, bare metal surface) or you have some other wiring that's damaged...
    view full answer...
  • Does Tekonsha Trailer Wiring that Fits 2020 Jeep Wrangler Allow Signals to Pass Through
    The connectors of the Tekonsha kit part # 118786 that fits your 2020 Jeep Wrangler Unlimited are pass through. If they were not the vehicle taillights would not function after the install. What this kit is designed to do is detect the signals that are passing through to the vehicle taillights and then send that info to the converter box which then draws power from the vehicle battery to power the trailer taillights.
    view full answer...
  • 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. Other kits require splicing instead of using the factory wiring harness quick connects located behind the driver's and passenger's side tail lights.
    view full answer...


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Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Jameson C
Expert Research:
Jameson C
Employee Adam R
Expert Research:
Adam R
Employee Lindsey S
Edited by:
Lindsey S
Employee Joshua S
Video Edited:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Dustin K
Video Edited:
Dustin K
Employee Chris R
Video Edited:
Chris R
Employee Jonathan Y
Video Edited:
Jonathan Y
Employee Cole B
Installed by:
Cole B
Employee Wilson B
Updated by:
Wilson B
Employee Alexander C
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Alexander C
Employee Isabelle B
Updated by:
Isabelle B
Employee Ronnie R
Written by:
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Employee Shane H
Test Fit:
Shane H
Employee Conner L
Test Fit:
Conner L
Employee David F
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Employee Ryan G
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Ryan G
Employee Bradley B
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