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  1. Custom Fit Vehicle Wiring
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  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 4 Flat
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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 # 118384
Our Price: $34.78
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Custom Fit Vehicle Wiring

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Tekonsha Custom Fit Vehicle Wiring - 118384
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Quickly and easily install a 4-way trailer connector on your vehicle. This T-One typically plugs directly into the back of your factory-installed 7-way connector so you can retain the 7-way and also pull a trailer that has a 4-pole flat. 1-800-496-5010 to order Tekonsha custom fit vehicle wiring part number 118384 or order online at 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 - 118384

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • No Converter
  • Tekonsha

Quickly and easily install a 4-way trailer connector on your vehicle. This T-One typically plugs directly into the back of your factory-installed 7-way connector so you can retain the 7-way and also pull a trailer that has a 4-pole flat.


  • Provides a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights
    • Retains functionality of factory-installed 7-way, RV-style connector (if present)
  • Connects quickly and easily - no cutting or splicing of wires
    • Locate connection points behind rear bumper
    • 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 behind the rear bumper. If you have a factory-installed 7-way, blade-style connector, the T-One will plug in between the 7-way and the OEM socket.

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.

118384 Tow Ready T-1 T-Connector - 4 Wire

Installation Details 118384 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 - 118384

Average Customer Rating:  4.8 out of 5 stars   (404 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle. This T-One typically plugs directly into the back of your factory-installed 7-way connector so you can retain the 7-way and also pull a trailer that has a 4-pole flat.

2004 Chevrolet Colorado

Do not use etrailers link for recommended harnesses when buying a hitch. Did not fit, and was for a vehicle if it already was equipped with a wire harness, why would you by a T wire harness if you already had a harness? The only recommendation that came up. Now they are trying to make money on the return. Use [online] instead, less hassle, faster and better.

GMC Sierra

As easy as it gets to add light power at the hitch. Perfect fit into the OEM connector behind the bumper on my GMC Sierra.


Straight forward install. Works as inte nded.

2013 GMC Sierra

Have been looking for a T-connector for my trailer lights for two years. Truck has a seven pin connector built-in. Wanted my GMC emblem to light up when the breaks are applied. Was getting ready to cut and splice wires when I looked on the internet and learned about Found the T-connector I needed. Took 5 days to arrive after ordering, and 5 minutes to install. Works great !


Slow start to a good impression but everything worked out.
1. It started with a delivery delay; I live two hours from the manufacturer but it took 3 weeks to get me my harness. When the error was found they over-nighted the harness to me.
2. The wiring in the harness was loose and would lose connection, disabling the lights. Pushing a connector back in to place, crimping it down and wrapping it in electrical tape solved that issue.
That was a month into owning the harness. It's been a year now and I've had no problems. I'm pleased with the compatibility and ease of which it took to install.

2012 Toyota Tundra

I have a 2012 Toyota Tundra and I recently bought a pre-owned Leer camper shell. I used this harness to wire up the third brake light. I also used the brake light module. This setup worked perfectly and resulted in a neat and clean professional installation. Thanks etrailer, you had everything I needed for a successful prefect installation.


This wiring harness fit good, was easy to install and the price was not to bad.


Makes for cleaner installation of tailgate light bar.


The box might fool you. If you wanted the harness for a jeep it is not listed on the box and the box photo shows a power converter. Actually in the box as pictured or it would be 5 stars. Making me double check the pn was compatible back on etrailer site. Installed as per website no issues there.

2012 Jeep Liberty

Parts came as described. Impressed with the weight of the hitch. It was well built.


Perrrrfect literally Less than 10 minutes for a complete install. Perfect fit

2013 Toyota Tacoma

Does not fit vehicle as described on web age. Charge for shipping to return item. As the problem is their poor match up of product and vehicles the charge for returning items should be paid by them. Basically false advertising! DO NOT TRUSS etrailer. Go somewhere else.

Some vehicles have a factory connector that will not come apart for this product to plug into, so the connector ends have to be cut off and hardwired together. We mention this in the tech tips when going through the fitguide.
-- Etrailer Expert Sierra K - 05/11/2022

Chevrolet Silverado

Installed over a year ago and works perfectly. It was easy to install and looks great on my 2020 Silverado.


trailer hitch went on very easy and plug was just as good


Great product as advertised. Plugged right in wire and loom plenty long . Highly recommend


Doesn't fit 2012 Toyota Tacoma

You mentioned that it did not fit the Tacoma. I wanted to see if you could explain in more detail how that it didnt. Did your Tacoma come with the factory seven way?
-- Etrailer Expert Jenny N - 07/21/2022
Thanks for responding. I have a 2012 Toyota Tacoma 2 - door, 4wd. I dont see a factory 7 way. The box doesnt list a Toyota.
-- comment by: Lynn - 07/26/2022
The 118384 harness does fit a variety of vehicles, mostly trucks, that have seven ways already installed and it will not list every fit on the box.. It is meant to plug in line with the US Carr connectors in the seven way to provide the 4 way. If a four flat is all that you need then I recommend part # C55513 for your 2012 Toyota Tacoma instead. I will have our customer service team email you return instructions.
-- Etrailer Expert Jenny N - 07/26/2022

2016 Jeep Grand Cherokee

Purchased this hitch for my new 2016 Jeep Grand Cherokee Laredo online after being quoted a $700 installation price at my local Chrysler Dealership. After doing some online searching and reading multiple reviews I decided to give these folks a try. My husband and I watched a very detailed video explaining 3 different hitch options for my Jeep and quickly decided for the price it was worth giving it a try. From opening box to install was less than 20 minutes that included connecting trailer light kit that I purchased extra $$.$$. You can barely see it under my JEEP. I'm very pleased and can't hardly wait to use it. Thanks again you helped me prove my to my husband that it would work and saved me $600!


This item is awesome . Plugs right in with no cutting or splicing and looks and works excellent even after 1 year

2014 Jeep Grand Cherokee

Bought a trailer hitch, and wiring harness for my 2014 Jeep Grand Cherokee. etrailer was fantastic, right on the money with the videos and it was very helpful in choosing the right hitch. Very easy to install.


Worked awesome


On my part I ordered the wrong wiring harness, was returned and replaced with the one I want with ease. Very happy with purchase


Search hi and low to find what I needed or even for someone who even understood what I needed. I had no luck until I search on They had exactly what I was looking for. Ordering was simple and delivery was quick. They even check in with me before durning and after shipping. I love this site. I'll definitely shop here first next time.

2016 Jeep Grand Cherokee

I purchased a trailer hitch (C13182) and wiring adaptor (T-One 118384) for my 2016 Grand Cherokee. Received it within a few days and fit was perfect! Only took all of ten minutes to install with the help of my 5 year old. Thank You!

2009 Jeep Liberty

The hitch is very good, fit like a glove, BUT, the electrical connecter doesn't fit anything. The fine print on the directions says for a factory wired vehicle to add on a 4 pin connecter. My 09 Jeep Liberty was not factory wired so I'm out the money I paid for it. Thanks.

If you do not have a factory 7 way you will need this kit first: Item # 118554
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
-- Etrailer Expert Sierra K - 10/06/2021


Like this wiring harness so there’s no cutting no splicing everything stays OEM and it cuts installation time

Show More Reviews

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

  • No Power on the Running Light Circuit on a 2000 Chevy Silverado z71 Towing a Boat Trailer
    There is a possibility of a relay or fuse related to tow package wiring either in the power distribution box or in the in-cab fuse panel that you can check. Look in the vehicle owners manual for all fuse and relay locations and check those. If the running light circuit shows no power on the 7-Way on the truck then that does eliminate the problem as being with the trailer. On the chance that it may be related to the trailer, it would most likely be a ground issue. You can check all the...
    view full answer...
  • Locating and Repairing Ground Problem in Wiring of Boat Trailer
    It sounds like you are on the right track with the ground problem. Check your trailer connector on the Grand Cherokee, and make sure the white wire is grounded to the frame of the vehicle. Even though your trailer works fine when connected to your truck, you still might have a weak ground on the trailer. It is not unheard of that a given trailer will work fine with one vehicle, but not with another. Check the grounding point where the white wire from the connector attaches to the trailer...
    view full answer...
  • Installing Pilot Automotive LED Fire Strip # 36049 on 2002 Chevy Silverado
    What you are describing is almost certainly a ground problem. If you are hardwiring the Pilot Fire Strip into place, you will need to make sure that BOTH ground wires are attached to clean bare metal on the truck frame or chassis (see photo). Leaving the 4-pole connector on the Fire Strip and installing a 4-pole connector on your truck like part # 118384 would would be your best bet, as there would be no cutting or splicing required.
    view full answer...
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  • Installation Instructions for the Tow Ready 4-Pole Harness for a 2010 Toyota Tacoma
    Under the rear bumper, near the driver side of your 2010 Toyota Tacoma there will be a plug with a cap on it that you will remove and plug the 4-Pole Trailer Adapter # 118384 into. I attached installation instructions and video for this product for you to check out that shows you how to install it.
    view full answer...
  • Trailer Wiring Harness Recommendations for a 2012 Jeep Liberty without a Tow Package
    Part # 118384 is designed for Jeep Liberties with a factory tow package. Without the factory tow package, not all functions will work. In order to make it function, you will need to head to your dealer and have them re-flash either the Body Control Module BCM or Power Control Module PCM to fully activate that port. Either way you would not need a relay.
    view full answer...
  • Is a Tail Light Converter Needed When Using a # 118384 with a Trailer With Combined Tail Lights
    The 4-Pole Trailer Adapter # 118384 that you referenced will not require a converter to be used with your trailer that has combined tail lights. The 4-way will have the correct voltage on the 4 circuits to be used with your trailer. GM will have already converted the signal from the separate signals like what are on your 2006 Chevy Silverado tail lights to a combined tail light circuit.
    view full answer...
  • No Tail Light Function on 16 ft Car Hauler Towed by a 2004 GMC Sierra 2500
    Based on your description, it sounds like your truck has a 7-way trailer connector. Anytime your trailer lights are not functioning properly, it is best to isolate the issue to either the truck or trailer. It sounds like you have already started some of the troubleshooting, but I will list the steps from the beginning just in case. The first and easiest step to take is to check the vehicle side and trailer side connectors for any corrosion. You said your wiring looks new, so this may...
    view full answer...
  • Troubleshooting Factory Brake Controller of 2015 Dodge Ram 1500 Not Showing Voltage on 7-Way
    Your problem could be as simple to fix as cleaning the pins on the 7-way of the trailer and truck. It's very common that corrosion or dirt prevents the brake controller output circuit from making a solid connection and preventing the controller from being able to work. Also, volt meters typically don't put enough of a draw on a brake controller circuit for it to register as a trailer being connected and allow it to work properly. Try cleaning the pin of the connector and then inspecting...
    view full answer...
  • Interior Lights In Horse Trailer Not Working After New Tow Vehicle
    If the only thing that has changed on your trailer is that it is now being pulled by a different vehicle then that is most likely where the issue resides. Generally speaking, the interior lights are powered by either a 12 volt battery on the trailer and is then charged by the 12 volt power circuit on the 7-way or they are just ran directly to the 12 volt power circuit on the 7-way. Therefore, the issue you are having is most likely that the 12 volt power circuit on the 7-way is not active...
    view full answer...
  • Troubleshooting Running Lights No Longer Working on Boat Trailer
    It sounds like there might be a weak or bad ground on the trailer wiring that maybe just took a couple of rides to fully present itself. The first thing I recommend doing is simply inspecting the 4- or 5-Way connector on the boat trailer. Look for any corrosion or debris inside the pins that needs to be cleaned out. Also inspect the wiring right behind it to make sure nothing is pinched and they are all fully secured to the connector. Next check the harness' main ground and make sure it's...
    view full answer...
  • Fuse Installation to Activate 4-Pole Trailer Wiring in 2009 Chevy Silverado 1500
    If your 2009 Silverado has the factory tow package it could still be missing the fuses required to activate the tow wiring to which you connected part # 118384. This part is intended for vehicles that have the factory tow package and 7-way trailer socket. Install any missing fuses/relays that are labelled trailer or tow. Be sure to use fuses of the correct amperage value for each location in the power distribution box under the hood. The fuse locations you referenced, right stop/turn and...
    view full answer...
  • 4-Pole Trailer Adapter for GM trucks with Factory 7 Way for a 2007 Chevrolet Silverado
    You are exactly correct, the 4-Pole Trailer Adapter for GM trucks with Factory 7 Way, part number 11838, will provide you with a 4 way connector. The 7 way will still function as well. The adapter would install inline between the two sockets, just as you describe.
    view full answer...
  • No Running Light On My Trailer When Connected To My 2011 Ram Sport
    Under the hood of your 2011 Dodge Ram there should be a 20 amp fuse for the trailer running lights. It is a fairly common problem with your generation of truck that fuse ends up blowing. There should be a legend on the fuse box or you can find it in your owners manual that details where all the different fuses are. Use that to find the correct fuse and replace it.
    view full answer...
  • Trailer Running Light Fuse Location 2016 Ram 3500
    I pulled up a copy of your owners manual online and it looks like F29 is the fuse slot you are looking for for the trailer running lights circuit. This will be a blue 20 amp cartridge fuse.
    view full answer...
  • 4-Way Recommendation for Installing Light Bar on 2015 Nissan Frontier with 7-Way
    Sounds like your 2015 Nissan Frontier has a 7-way installed on it already. What you would need to also install a 4-way with it is the part # 118384. This will install inline with your 7-way and give you a 4-way for the light bar.
    view full answer...
  • No Power on Tail or Brake Light Pin of Part # 118384
    If you are using the # 118384, and are not getting any signal on the connector for the brake or the tail light, you most likely have blown or missing tow package fuses. These fuses are typically located in a fuse box under the hood, but their location can vary according to the year, make and model of your truck. Your owners manual should have a fuse diagram showing which fuses protect which circuits, as well as the location of the fuses.
    view full answer...
  • Troubleshooting 2011 Dodge Ram No Running Lights on Trailer, Brakes and Turn Signals OK
    Under the hood of your 2011 Dodge Ram there should be a 20 amp fuse for the trailer running lights. It is a fairly common problem with your generation of truck that fuse ends up blowing. There should be a legend on the fuse box somewhere that details where all the different fuses are. Use that to find the correct fuse and replace it.
    view full answer...
  • Troubleshooting Trailer Lighting That Stops When Headlights of Vehicle are Turned on
    What you described is the classic insufficient ground scenario so finding a way to improve the grounds will fix the problem. Try improving the connection of the main ground wire of the trailer wiring harness. Make sure it is attached to a clean metal surface. Or you can run all of the trailer wires back to the main ground. This is actually the ideal solution. But you can also check the current grounds for the lights to make sure they are making a solid connection to a clean metal surface.
    view full answer...
  • Does T-One Vehicle Wiring Harness 118384 have Combined Brake Light and Turn Signal Functions
    Tow package wiring on a vehicle is already converted to combine the brake and turn signal lights onto the same circuit which is what trailers use. Wiring harness # 118384 Tees in line with the factory 7-Way wiring and provides a 4-Way flat connector in addition to the factory 7-Way so when using it the brake and turn signal lights will also be on the same circuits.
    view full answer...
  • Will Tow Ready T-One Connector with 4-Pole Connector Fit 2008 Chevrolet Silverado
    The Tow Ready T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118384 is confirmed as a fit for the 2008 Chevrolet Silverado. This 4-Way trailer connector will plug into your Silverado's wiring behind the factory 7-Way connector at the rear of the vehicle. I've attached an installation video of this connector on a similar vehicle for you. I've also attached links to the wiring fitguide and the fitguide product categories for your 2008 Chevrolet Silverado for you.
    view full answer...
  • Installing the Tekonsha T-One # 118384 on a 2010 Jeep Liberty
    If you check out the linked installation video of the Tekonsha T-One # 118384 being installed on a 2012 Jeep Grand Cherokee you can see where the plug is located. If the directions for your wiring harness say that the connector should be located on the driver side of the bumper then this is where it should be for your 2010 Jeep Liberty. Please note that not all 2010 Liberties have the US car connector. If that is the case for your Liberty then you will need to install the T-One # 118554...
    view full answer...
  • Installed 7-Way and 2012 Jeep Grand Cherokee Dealer Reprogrammed But No Brake Lights/Turn Signals
    If your 2012 Jeep Grand Cherokee did not come with a factory installed 7-Way then if you plug one into the wiring at the back of the Jeep the 7-Way would not function. Like you already did, you would go to the dealer and have them reprogram the computer to get the newly installed 7-Way to function. If everything was installed properly then it should work. If not then they may have made a mistake in the reprogramming process. Or, it could be that there is a fuses or fuses or even relays...
    view full answer...
  • Drivers Side Brake and Turn Signal Lights Not Working on a 2012 Ram 3500 4x4 Cummins Diesel
    When a light is only working periodically that is usually an indication of a weak ground connection or a loose wire. But on a newer truck like your 2012 Ram 3500 this does not seem likely. The trailer connector having power is not surprising. That means that the trailer wiring is independent of the truck lights. I would start at the front and work my way back. You could have something going on with the fuse and/or relay (if equipped) on that side. Use the truck owners manual to find all...
    view full answer...
  • Keep Blowing 20 Amp Running Light Fuse when Connecting Trailer to 2012 Ram 5500
    There is a short circuit somewhere that is causing the fuse to blow. A short would cause excessive power draw. Since it only happens when you plug in a trailer it is likely that the short is in the trailer connector or the wiring to it. You will need to make sure that there is no corrosion build up on the pins of the connector but also on the inside of the connector where the wires attach. Also check for any frayed or pinched wires touching metal and fix as needed.
    view full answer...

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