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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 # 118384
Our Price: $37.68
You Save: 27%
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. 1-800-940-8924 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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  • Reviews (445)
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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   (445 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.

2011 Chevrolet Silverado

I used this harness to add a tailgate strip light to my 3011 Silverado. The whole process including installing the light strip took 45 minutes. The harness plugged in in minutes and works beautifully.

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 !

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.

Ron G.


I installed this unit on my truck one year ago. It was perfect then and it is still working perfectly without issue.


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.

Don M.


The harness has held up great. Needed no adjustments after original installation.

GMC Sierra

Perfect fit for 2022 Sierra GMC . This leaves your 4 pin vacant to plug in your boat trailer etc


Exactly as described, wires in nicely, has been working flawlessly since the installation!

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!


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!

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.

2014 Jeep Grand Cherokee

Fit just like it should, engages securely and performs correctly. Nothing else I can ask for


Website very easy to operate and fubd exactly the right part to fit my truck/trailer !!! Videos were very helpful even telling me what sockets and wrenches I needed to complete install by myself and Im a carpenter not really mechanically gifted. Will definitely use again without hesitation!!




World class customer service


Always worked for me when purchased in the past so I didn't expect anything less this time.

Reginald W.


Ive had no problem with this item even thru a harsh winter use. Just make sure you use a little diox grease on the electrical pins so moisture doesnt ruin the contact

Etrailer Expert

Mike L.


@ReginaldW Good advice, dielectric grease like # 11755 does a great job of keeping moisture out of your electrical connections.


great trailer hitch at fair price.


Fit perfectly, and the [online] video was very helpful


Easy to use web site - got the correct part - I have already ordered more parts - this time for my trailer!!! I will always choose etrailer for my parts



It was so easy to install and I have not had any issues with it. Best add on I ever added!!!


Works perfectly

2022 Ram 1500

OEM quality, plugged right in as advertised. My second purchase of a harness of this type from etrailer for a new vehicle, and will do so again.


Installed myself in about 30 minutes. 06 Silverado crew cab. Fit right up to factory fitting that was hidden up on top of the spare tire.

2015 Jeep Grand Cherokee

Super easy installation and the addition of the 7 pin means that it is upgradeable. Perfect for me.


Excellent product and easy to install! Finished up the installation with products 118144 and 118140 for a clean looking install.

2017 Jeep Grand Cherokee

I recently purchased a new 2017 Jeep Grand Cherokee. However, the vehicle was not equipped with with a trailer hitch but came pre-wired for trailering. I asked if the dealership could install a hitch/wiring and was informed that they subcontract the work to a local trailer rental company. I went to the company and was told it would cost approximately $400 and I would have to leave my vehicle with them for four hours, which would have been very inconvenient because I live 50 miles away. As a result, I researched alternatives online to see if I could install the hitch and wiring myself. had the best customer reviews and help videos, so I placed an order for the hitch and wiring harness. My wife and I installed them yesterday, which took about an hour. I saved $270 from what the trailer company was going to charge me. Very happy with the purchase.

Gary G.


Working fine.

2014 Jeep Grand Cherokee

It is so easy-to-install

Show More Reviews

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

  • Troubleshooting Ram Brake Controller Not Showing Connection to Trailer
    Typically the problem you are having is caused by corrosion on the brake controller output pin of the 7-way on either the vehicle side or the trailer side. If you take sandpaper to all of the pins this normally is the easy fix for this. The fact you are seeing a dim flicker on the tester when plugged into the vehicle is a good sign as that indicates that the circuit is complete from the controller. What you are seeing is basically the controller testing for a trailer connection with a...
    view full answer...
  • Boat Trailer Pulled by 2001 Chevy 1500 Has Lights That Will Not Work When Brakes are Applied
    I would suspect a poor ground connection on the trailer. Most trailers use a ground connection at the front of the trailer, with each lamp picking up its ground connection by its physical contact with the trailer frame, in effect, using the trailer itself as part of the ground circuit. Take a look at the grounding point for the trailer connector, it can usually be found on the trailer tongue near the coupler. Make sure that this ground connection is tight, and connected to clean metal....
    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...
  • 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...
  • Where Is Fuse For 12v Power To 7-way Connector In 2020 Ram 1500?
    I check the owner's manual of your 2020 Ram 1500 and the fuse for the 12v power pin on your 2020 Ram 1500 is located in the fuse box underneath the instrument panel on the driver side, and the fuse is F01 which is a 30amp pink fuse. Check to make sure the fuse is not blown/missing, as this is more than likely causing the pin to not have power. I included a link to a helpful article on wiring for you to take a look at.
    view full answer...
  • How to Add a 4-Way to a Vehicle with a 7-Way Easily
    What you would want is the part # 118384. This harness installs in line with the 7-way at the rear of your Toyota Tacoma and gives you an additional 4-way to match what is on your trailer without the use of an adapter.
    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...
  • 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...
  • Reason for Blown 12V Trailer Connector Fuse on 2014 Ram Truck
    Usually a blown fuse is caused by some kind of short from a damaged or exposed piece of wiring. If the 12V fuse on your truck is blown, I recommend tracing the wiring going to the 12V pin on your 7-Way (1 o'clock position) and checking for any exposed areas that might be making contact with bare metal or another wire. Also inspect the 7-Way itself for any debris or corrosion that might be built up behind the pin. I took a look at the online owner's manual for your 2014 Ram and it looks...
    view full answer...
  • Why Would Interior Lights of Horse Trailer Not Function If Outlets Work
    It's probably a breaker that is tripped that controls the interior lighting. See if you can find the breaker box (should be near the battery) and then check to make sure all of the breakers are the right direction.
    view full answer...
  • Inline 4-Pole Trailer Connector for 2001 Ford F-150
    If your OEM 7-way can be unplugged from tow package harness the rear of the connector, I'd recommend the Tekonsha # 118384 which would plug inline at that connection.
    view full answer...
  • Fuse Location for 12-Volt Accessory Power Feed to Trailer on 2012 Dodge Ram 1500
    This typically occurs because of a blown or missing fuse in location J01 in the TIPM box located near the battery. The fuse is a green 40 amp cartridge type fuse. If the existing fuse is blown, be sure to check the power feed circuit on the trailer, making sure that there aren't any shorts in that wiring run. Also check the trailer connector on the tow vehicle and on the trailer itself. Check the pins and sockets for corrosion, sometimes corrosion can spread to the interior of the plug...
    view full answer...
  • Trouble Shooting Loss Of Power At Factory 7 Pole Plug When Adding 4 Pin Adapter On A 2018 Ram 1500
    On your 2018 Ram 1500 I would start by removing the adapter and testing your factory plug. If you are getting power there then it is the adapter. Check the pins to make sure one didn't get bent to the side. Also make sure the adapter is completely seated into the factory plug. It can be hard to get those to click into place sometimes. If you are not getting power at the factory plug then check the wires coming out of the back of the factory plug for any damage. Check fuse F30 in the fuse...
    view full answer...
  • Additional 4-Way for 2022 Ram 1500 for Powering LED Light Bar
    The easiest way to add a 4-way to the trailer wiring at the rear of your 2022 Ram 1500 that has both a 7-way and a 4-way would be the part # 118384 which will plug inline with the 7-way and give you an additional 4-way for the LED strip.
    view full answer...
  • Troubleshooting Brake Controller of 2014 Ram 2500 Stopped Working When Accy Circuit Fuse Blew
    If the guy who installed your brake controller did his homework he should have gotten power for the brake controller from the factory wiring that was designed for brake controller installs and not from the 12 volt accessory circuit that you replaced the fuse on. So I would check to see where the black wire of you brake controller wiring is ran to. There should be a separate fuse for the brake controller power circuit though which would be the correct one to replace to get the controller...
    view full answer...
  • 4-Way Harness Recommendation for 2013 Chevy Silverado 2500HD for Plugging In Camper Shell
    Your 2013 Chevy Silverado 2500HD should have a 7-way trailer wiring harness already so to give you a 4-way to plug your cap into you would want the # 118384. This will plug in line with the 7-way and give you a 4-way.
    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 Brake Controller Not Showing Connection
    Have you checked the pins of your 7-ways for corrosion? Typically when this exact problem occurs on trailer wiring the issue is that there's just a bit of corrosion on the 7-way pins which then prevents the output circuit of the controller from making a solid connection. If you take some sandpaper to the pins of the connector you should see the circuit make connection again. I also attached a link to a page that has troubleshooting info on brake controllers for you to check out as well.
    view full answer...
  • Where Is the 12 Volt Trailer Connector Fuse on a 2015 Ram 1500
    It would appear judging from the online version of the owner's manual for your 2015 Ram 1500 that the 12 volt power on the 7-way is tied into the pink, 30 amp fuse in the F30 slot within the power distribution center (PDC). If this is not correct then you would need to reach out to the dealer.
    view full answer...
  • 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...
  • 12V Fuse Location for 2017 Ram 3500
    I took a look at the online owner's manual for your 2017 Ram 3500. It looks like the fuse related to the 12V pin at the 7-Way should be located at the F30 position inside the power distribution center (in the engine compartment). This will be a 30 amp pink fuse. You will just want to make sure this fuse is present and in good condition. Other fuses on your Ram related to towing are as follows: F28 - Trailer Tow Backup Lights - 20 Amp Blue F29 - Trailer Tow Parking Lights - 20 Amp Blue F53...
    view full answer...
  • Recommended 4-way Connector For 2020 Ram 1500 Classic For LED Tailgate Light Bar
    For your 2020 Ram 1500 Classic you will want to use the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118384 you will want to plug in in-between the factory wiring harness and 7-way connector to give you a 4-way connector you can use for your LED tailgate light bar without taking up your current trailer connectors. I included a video of the # 118384 for you to take a look at.
    view full answer...
  • Will T-One 4-Flat Work on 2024 Chevy Silverado Without Throwing Codes
    Yes, the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118384 will work on your 2024 Chevy Silverado and not throw any codes. This is what most people use it for, to make installing that light bar easier.
    view full answer...
  • Wire Color Functions Typical of 7-Way on Trailer Red, Black, Blue, and Green
    For 7-way wiring typically the red wire is for the left turn/stop signal, the black wire is the 12 volt power accessory circuit, the blue is for brake controller output, and the green is for running lights.
    view full answer...
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