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  1. Custom Fit Vehicle Wiring
  2. Tekonsha
  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 4 Flat
  6. No Converter
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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

Item # 118540
Our Price: $40.24
You Save: 45%
Custom Fit Vehicle Wiring

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Tekonsha No Converter Custom Fit Vehicle Wiring - 118540
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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 - no cutting, splicing or tapping required. 1-833-496-1390 to order Tekonsha custom fit vehicle wiring part number 118540 or order online at 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.
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  • Reviews (417)
  • Q & A (0)
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  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring - 118540

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • No 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 - no cutting, splicing or tapping required.


  • 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 - no cutting or splicing of wires
    • Locate connection points at the rear, on the passenger's side
    • Plug in T-connector
  • Constructed of 16-gauge bonded wire
  • Comes with dust cap for 4-way flat connector


  • Maximum amperage: 7.5 amps per circuit
  • 1-Year limited warranty


This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located beneath the rear of your vehicle, on the passenger's side.

Once installation is complete, the 4-way flat connector will be stowed beneath your vehicle, near the trailer hitch. 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.

118540 Tow Ready T-1 T-Connector - 4 Wire

Installation Details 118540 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 - 118540

Average Customer Rating:  4.9 out of 5 stars   (417 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 - no cutting, splicing or tapping required.

2017 Ford Explorer

Great product. Great customer service….Kudos to Quinn and Wayne! Great instructional material, especially the videos. I only had two minor issues. First, the rubber muffler hangers were buggers to remove; second, the instructions for the wiring harness indicate the 2017 explorer has two plugs which the Tekonsha T connector plugs into, problem was my explorer only has one plug? but in short order between Quinn and Wayne, I learned I only needed to plug one side of the Tekonsha T connector into my plug and cap the other side of the T with the cap I removed from my single plug. Long story longer, I took my vehicle to [moving company] who checked out the wiring with their test gizmo and all was perfect!
Big thank you to the etailer team!!!

My hitch and wiring harness have performed Flawlessly! Highly recommend etrailer.
Michael - 11/11/2022


Very simple install on the wiring harness.
is my 2nd hitch installation and should last My lifetime.


I installed this 1 year ago on my 2015 Ford Explorer. The installation instructions were very clear and easy to follow. The install including the trailer light kit took less than 1 hour and I was so pleased with the fit. It looks like it was a factory installed option from Ford. I give this a 5 out of 5 rating!

2015 Ford Explorer

Easy to install, seems like great quality. Have not had a chance to use it yet.

2016 Ford Explorer

This harness worked great. Plug and play on my 2016 for explorer. Just a note for anyone that may have the same issue, most trailers actually use the ball in the hitch for the “ground” so when I first connected trailer lights did not come one. However one a put weight on the ball and made a good connection lights worked great. Wonderful product and would recommend

2014 Ford Explorer

Perfect fit. I watched the video for installation and found that my 2014 Ford Explorer didn’t have the same connection pictured. Mine terminated with a cap instead of being connected in series like the video.

Once I figured that out with the help of customer service (who was awesome by the way) I pulled it off and hooked it right up. Zero problems. These folks do a great job of knowing their product and providing great service. This is my third hitch install with


Perfect fit harness, supplied wire ties a bit short but I have plenty of my own. Also wrapped exposed wires with silcone tape for further weather protection.


Customer service is horrible. Took a month to get replacement parts on part of this order, which were not in the original package.


Fit perfectly into the existing wiring of my 2012 Ford Explorer- complete plug and go; no splicing or taping required. Don't
Think it even took 10 minutes to do. Plenty of wire in the harness to route it to the hitch. Does exactly what was promised

2019 Ford Explorer

Fit great.looks factory. Thanks


Was told by local dealer to order hitch would take 4 - 6 weeks, ordered from etrailer on Monday and was delivered on Wednesday! Also etrailer had better price. Wow


Product does exactly what it says. Shipment was quick and installation was a breeze thanks to the trailer videos!

Still going strong! Ive had exactly ZERO problems with the wiring harness.
Michael - 04/26/2022

2011 Ford Explorer

Etrailer does a great job! Huge selection of products with great prices and fast delivery. I’m not sure what more I could ask for.

I needed a trailer wiring harness for my 2011 Ford Explorer. The part was in stock. It arrived quickly and exactly as described. The installation was quick and easy. Perfect! Thanks.


Easy install ( I hired someone). Plug and play.

2011 Ford Explorer

I just bought a new 2011 Ford Explorer, I need to tow a small utility trailer. I was unsure how this harness would be plugged in, but it was so easy a 5 year old could do it. I found the Ford provided trailer harness behind the right rear tire above the muffler, this harness clipped right in, I used the original cap on the other end to cap the male end off.
I have only one bad comment, the zip ties provided are not long enough to go around the trailer hitch pipe. So I doubled up or used ones I had. There is plenty of length to get me to the hook up. Make sure you keep it away from the hot pipes. See attached pics. I submitted a couple questions to and they were very responsive.


Excellent products and service; plus delivery, thanks

2018 Ford Explorer

Good product but it didn’t fit my 2019 Ford Explorer. Not sure which connector it will need

This wiring is a match for a 2019 Ford Explorer with a factory tow package. Be sure to take the plug cap off before plugging the connector in.
-- Etrailer Expert Sierra K - 05/05/2022

2013 Ford Explorer

The wire was exactly as described and easy to install. The installation videos provided with the wire were fantastic and made the job really easy.


13 Ford Explorer

2018 Ford Explorer

Great product! Have two existing connectors underneath my 2018 Ford Explorer XLT. Had to disconnect both to determine which one was correct - no big deal. Ran the wiring pretty much straight back to the bumper and over to the hitch. Had to use a couple longer zip ties.


Received my order in good time have hot tried to install anything yet, you will have to give me a few weeks to try and put it on vehicle.


Easy install. Works well. Recommended.


Easy to install, but same complaint as every other reviewer - just size up the zip ties already! Daisy chaining them to secure the cable is annoying and so easy to fix.


Products are excellent quality, the customer service is great and installation is simple with easy to follow instructions. I have purchased several items from etrailer and the videos and instructions are helpful and easy to follow.


Plug and play could not be simpler.

Show More Reviews

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

  • Connection Point for a Tow Ready Wiring Harness on a 2011 Ford Explorer Limited 4x4
    On the 2011 Ford Explorer, the connection point for the T-One Vehicle Wiring Harness, # 118540, is located underneath the rear of the vehicle, on the passengers side. The connection point will be behind the rear tire and have connectors matching the T-Connector harness. I have included a link to the installation details that includes pictures that should also help.
    view full answer...
  • Differences Between Available Trailer Wiring Harnesses for 2012 Ford Explorer
    You can use the Tow Ready # 118540 with no problems, as long as your Explorer is equipped with the connector shown in the photo I provided. The signals used at this connection point are already converted, so no additional converter is needed. This connection is circuit protected by existing fuses, so there is no risk involved with using this harness. The Curt harness that uses the converter attaches directly behind the tail lights, at which point the signals are not converted, which is...
    view full answer...
    Image 1 for
  • Trailer Wiring Harness for a Base Model 2013 Ford Explorer
    If you only have the one end under your 2013 Ford Explorer and you cannot find the other end, I would recommend not using harness # 118540. Instead, you could use # C56093 which plugs in line with the tail light wiring. You will also need to run a power wire to the vehicle battery. This powers the trailer lights and protects the vehicle wiring. I have included a link to an FAQ on routing the power wire for you.
    view full answer...
  • 4-Way Trailer Wiring Harness Recommendation for 2014 Ford Explorer
    To add a 4-way to your 2014 Ford Explorer what you need is the wiring kit part # 118540 which is a confirmed fit and plugs right into the connector at the rear of your vehicle. I attached an install video for this for you to check out as well.
    view full answer...
  • Troubleshooting Stop/Turn Circuits Not Working After Tekonsha Harness # 118540 Install
    The T-One Vehicle Wiring Harness # 118540 with it's single connector should be tapping into the vehicle stop/turn signals. If yours isn't active but the vehicle signals are working I'd first try unplugging and plugging the connectors in to see if there's maybe just a connection issue that needs to be cleared out. Next I would check under the hood for any trailer wiring related fuses/relays and replace as needed.
    view full answer...
    Image 1 for
  • Trailer Wiring Recommendation for 2016 Ford Explorer
    For your 2016 Ford Explorer the T-One Vehicle Wiring Harness # 118540 that you referenced is exactly what you need. The 4-way harness like this is designed to activate just the brake/turn/running lights of a trailer. Check out the install video I attached for more info as well.
    view full answer...
  • Recommended Wiring Harness for 2013 Ford Explorer
    The Tekonsha T-One Vehicle Wiring Harness # 118540 referenced in your question is the correct harness and is confirmed to fit your 2013 Ford Explorer. The T-One connector will plug directly to the harness that is located beneath the rear of your vehicle, on the passenger side. There should be both a black and gray connector next to each other. You will be using the black connector. Once located, you will need to separate the two connection points on the plug by pressing on the locking...
    view full answer...
    Image 1 for
  • Trailer Wiring Install Location on 2017 Ford Explorer
    To install trailer wiring on your 2017 Ford Explorer like the part # 118540 you will need to locate the plug for it under the passenger side of the rear bumper. If you check out the picture I attached you can see where it is and also I attached an install video that shows where to find it as well.
    view full answer...
    Image 1 for
  • How to Install the Tekonsha T-One Trailer Harness on a 2016 Ford Explorer
    According to the installation instructions for the T-One Wiring Harness, # 118540, the tow-plug for the 2016 Ford Explorer is located at the rear passenger's side. Refer to the attached photo. The trailer wiring harness will connect to this OEM plug at your Explorer. I have also linked an installation video of the Tekonsha Wiring Harness being installed on a 2016 Ford Explorer for you to review.
    view full answer...
    Image 1 for
  • T-One Trailer Wiring Harness Installation Location on 2012 Ford Explorer
    Thank you for the photo of the connector you found on your 2012 Ford Explorer near the muffler on the passenger side. This is the correct trailer wiring connection point for an item like # 118540; you just need to remove its protective cover to get to the actual connector.
    view full answer...
    Image 1 for
  • Tekonsha T-One Vehicle Wiring Harness # 118540 Not Working on 2017 Ford Explorer
    I spoke with my contact at Tekonsha regarding the T-One Vehicle Wiring Harness # 118540 that you installed on your 2017 Ford Explorer. He said that on the rear driver side corner of your vehicle there are 2 factory connectors available, one is grey and the other is black. You just want to make sure you are connecting this harness into the black connector. Based on the issues you described in your question, it is likely that it has been connected to the grey port on your Explorer. If this...
    view full answer...
  • Troubleshooting a 2013 Ford Edge that Keeps Blowing Taillight Converter Boxes
    Usually when trailer wiring causes fuses to blow it is because there is a short somewhere on the trailer wiring. Before you replace anymore wiring components you need to track down that short and fix it so that you don't have to buy any more converter boxes than needed. I attached a couple FAQ articles that should help you troubleshoot and find the short.
    view full answer...
  • Trailer Wiring Compatibility with 2016 Ford Explorer Police Interceptor
    We install harnesses on many vehicles like the park ranger you mentioned and we have not seen any differences with the wiring harnesses on these Explorer models. I reached out to my tech contact at Tekonsha and he said that it is possible you are trying to connect the harness # 118540 to the incorrect connector because there are two that are very similar on the interceptors. He said there is a black connector and a gray connector that look very similar. The black connector is the one...
    view full answer...
  • Trailer Wiring Harness Recommendation for 2018 Ford Explorer
    For your 2018 Ford Explorer the 4-way trailer wiring harness you'd want is the T-One kit part # 118540 which is a confirmed fit and our easiest to install kit so I recommend it for you.
    view full answer...
  • 2017 Ford Explorer Parking Sensors Don't Work With 4-Way
    Thank you for your purchase from etrailer for your 2017 Ford Explorer of the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118540. The only reason I can think of why this may have happened is if you have plugged the harness into the wrong plug . On some models there is both a black and a gray factory connector, and you need to make sure you plugged it into the black connector. I have added a link below to a video install on a '17 Explorer for you as well.
    view full answer...
  • Troubleshooting Tekonsha T-One Harness 118540 In 2016 Ford Explorer Only Powering Trailer Tail Light
    The Tekonsha T-One Vehicle Wiring Harness # 118540 you installed in your 2016 Ford Explorer without the factory Tow Package is compatible with trailers that have incandescent or LED lights so that will not cause any issues. On some Explorers there are two connectors, a grey one and black one. When you installed the # 118540 did you notice if there was more than on connector? If there was you will need to connect into the black connector. Installing the connector in the wrong factory connector...
    view full answer...
  • Where Would Factory 4-Way Be on 2012 Ford Explorer
    If you had the factory 4-way on your 2012 Ford Explorer it would be hanging behind the rear bumper. We sell the part # 118540 which is the correct 4-way for your vehicle, I attached a picture of it's harness plugged in behind the rear bumper for you to check out as well. Look by the passenger side exhaust pipe.
    view full answer...
    Image 1 for
  • Where Does Wiring Harness Plug Into on 2018 Ford Explorer
    I have added a photo for you of where on your 2018 Ford Explorer you should plug in the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118540. The harness is black and will be up behind the rear wheel on the passenger's side. I have also added a link below to a video install of the # 118540 on an '18 Explorer.
    view full answer...
    Image 1 for
  • 5-Way Trailer Wiring and Hitch Recommendation for a 2012 Ford Explorer
    If you do not have a 4-way present at the rear of your 2012 Ford Explorer I would recommend you get a Tow Ready Custom Fit Vehicle Wiring Harness # 118540. This is a very simple install, I attached installation instructions and a installation video for you to check out as well. Once you have a 4-way you will be able to install a Adapter 4 Pole to 5 Pole Wiring Adapter # 47515. This will basically just plug right in to your 4-way and then will give you the fifth circuit that you could run...
    view full answer...
  • 4-Way Mounting Bracket Recommendation for 2017 Ford Explorer
    When we installed the Tekonsha trailer wiring kit part # 118540 on a 2017 Ford Explorer we used the install bracket part # 18144 and attached it to the bumper of the vehicle.
    view full answer...
  • Trailer Wiring Recommendation for 2016 Ford Explorer
    If you need a 4-way trailer wiring harness you'll want the part # 118540 which is a confirmed fit, or if you want the 7-way trailer wiring harness you'd want the part # 118272 which is also a confirmed fit. I attached install videos for both of these for you to check out.
    view full answer...
  • Troubleshooting The Quick Connections On The 2017 Ford Explorer And The Tekonsha Harness # 118272
    This Tekonsha T-One Vehicle Wiring Harness for Factory Tow Package - 7-Way Trailer Connector # 118272 harness is designed to be used with vehicles that already have a factory tow package. If you don't have that factory tow package, it may not fit. If you don't have the tow package, I recommend you use the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118540. If you do have the factory tow package, it should install to the connection located beneath the vehicle behind...
    view full answer...
  • Will Draw Tite Trailer Hitch for 2017 Ford Explorer Allow Hands Free Liftgate to Still Open
    The Draw Tite hitch part # 76034 is a great hitch option for your 2017 Ford Explorer with the hands-free liftgate sensors. You'd just need to kick your foot to either side of the hitch opening to activate the lift gate instead. I attached an install video for this hitch for you to check out as well. If you need trailer wiring you can add a 4-way very easily with the plug and play Tekonsha kit part # 118540.
    view full answer...
  • Included Hardware for Draw-Tite Max-Frame Trailer Hitch on 2018 Ford Explorer
    I reached out to Draw-Tite Directly and confirmed the hardware that is included is correct for The Draw-Tite Max-Frame trailer hitch receiver # 76034. The Draw-Tite # 76034 would be a great addition to your 2018 Ford Explorer. I attached the install video and a copy of the instruction manual for your 2018 Explorer to ensure a straight forward install. If you are planning on towing I recommend adding Tekonsha Harness # 118540 as it is offers plug and play installation. I included the installation...
    view full answer...

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