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T-One Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector

T-One Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector

Item # 118285
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Tekonsha 4 Flat Custom Fit Vehicle Wiring - 118285
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Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-One connector plugs directly into OEM tow package harness - no cutting, splicing or tapping required. 1-636-306-4830 to order Tekonsha custom fit vehicle wiring part number 118285 or order online at Free expert support on all Tekonsha products. Guaranteed Lowest Price and Fastest Shipping for T-One Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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  • Reviews (126)
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Tekonsha Custom Fit Vehicle Wiring - 118285

  • 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 harness. T-One connector plugs directly into OEM tow package harness - 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
    • Designed for use with a factory tow package
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Connects quickly and easily - no cutting or splicing of wires
    • Locate connection point behind rear bumper
    • Plug in connectors
  • Includes required relays to activate functions
  • Constructed of 16-gauge bonded wire
  • Comes with dust cap for 4-way flat connector


  • Maximum amperage:
    • Stop/turn lights: 7.5 amps per circuit
    • Tail lights: 7.5 amps per circuit
  • 1-Year limited warranty


This custom-fit T-One connector plugs into your vehicle's factory tow package wiring harness, which is located behind your rear bumper, on the driver's side. Once you've plugged in the connector, open your fuse box and locate the fuse position indicated in the instructions. Then insert the included relays.

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.

118285 Tekonsha T-1 T-Connector - OE Replacement 4-Flat

Installation Details 118285 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Reviews

T-One Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector - 118285

Average Customer Rating:  4.9 out of 5 stars   (126 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-One connector plugs directly into OEM tow package harness - no cutting, splicing or tapping required.


Didn't even have to take off a tail light. The car came with a dummy plug on it that I had to take off by sliding the red plastic away from the wired side then pressing the black part in the middle of the red slide while pulling off the connector. Wam Bam plugged in my new harness to that, and I got lights. Couldn't be easier. They shipped a couple of relays to but my trailer has LED so they are not necessary which is good cause my fuse block had a space but did not has connectors for it.
NOTE, the connector under the bumper is hard to get to so if you are unfamiliar with this kind of plug try taking one off under the hood that is easier to get too

Haul the trailer several times and never had a problem with it
Steven - 07/08/2022

2019 Chevrolet Equinox

High quality product. Plug and go. It doesn't get any easier than that/

Could not ask for a better product. Extremely pleased. Still looks like new.
Richard M - 06/12/2022


Plug in play harness. I watch the video from etrailer on this harness install. I check my vehicle to insure it had factory installed connector. Which my vehicle had l installed 118285 before installing the draw-tite hitch number 76419. I used a trailer light circuit tester. I have shared pictures of the circuit being tested the tool used and the vehicle connector that has to be removed.
Hope this helps you


The tow package arrived in a timely manner and in good condition. Installation went well thanks to the videos the company provided. The only issue I had was that the muffler rattled against the hitch no matter what I did. I rechecked my installation and followed suggestions from the retailer. I ended up using a universal muffler hanger that allowed me to lower the exhaust 1/2". This solved the problem, and the hitch has performed well over the last year and still looks great. I have bought from this company before and will buy from them again in the future.


The video was perfect. Found the wire harness tucked behind bumper. I would have never figured out the release clip with out the video help. Plug and play. My 2018 Terrain had 1 big relay already installed in K3 so mine was quick. I bought the tester to verify install. New hitch and wiring installed 1 hour and 20 minutes. Having the tool sizes listed helped having next to me on the ground while installing. About 11 inch height so I am getting a riser to make trailer level. Thank you for your customer service.


Quality of product is excellent, Delivery time exceptional, cost fantastic.

2022 Chevrolet Equinox

Everything fit just as expected and the installation videos are extremely helpful

2020 Chevrolet Equinox

This Wire Harness fit perfectly on the 2020 Chevy Equinox.It was like plug and play easy after mounting with a 4 pole flat mount.

2020 Chevrolet Equinox

Items purchased, Draw-tite trailer hitch and Tekonsha wiring kit for our 2020 Equinox. This was my first encounter with etrailer, and I must say I was impressed. From the initial order placement, I knew where my order was while in route and exactly when it would arrive. I had previously watched the installation videos on both products and they could not have been clearer. Total time from opening boxes, to tools put away was less than 2 hours. All parts are of quality materials and fitment along with reasonable prices. While this may have been my first experience with etrailer, it certainly will not be my last. Thanks to all for making everything go smoothly.

by: 06/27/2022

Great product plug and play was very easy install


Easy to use and install...

2020 GMC Terrain

Videos extremely helpful.Product was all and even more than expected. The hitch went on without a HITCH, Sorry, couldn't help it. this is how it turned out. would buy again in a heart beat. Thanks


Easy Peasy! The hardest part was getting the factory connector apart.

My hitch continues to work well and the wiring kit not only works well, it fit like a glove! Everything was very easy to install, and the directions were easy to follow. Be assured, not only sent me everything I needed quickly, it all fit and was easy to install, all at a very good price. Thanks for great products and great customer service too!
B.C - 10/22/2021



Plugged right in easy install.
LeeRoy H - 12/31/2021


They made sure I had the correct parts needed for my car and were very friendly! Not to mention it came in way faster than I expected!! I love my tow package for my 2020 gmc terrain


Shipped fast and correct


It was very simple to install

2020 GMC Terrain

Plug and play. The relays would not go in the fuse panel. Not needed.

2019 Chevrolet Equinox

Very easy install. I watched the video before the install just to get an idea of what needed to take place. Got a little worried when I saw the guy using the fishing wire to pull the hardware through; I was thinking, where the crap am I going to find that at. Don't worry, it comes with it. Coolest thing ever and works just as easy as the video shows. Also, if you have a 2019 Chevy Equinox you do not have to widen the hole for the hardware to fit through as shown in the video, either chevy made the hole bigger or etrailer made the hardware smaller. Either way it went in flawlessly. Now I'm on the hunt for a new trailer. Oh, and the recommended wiring harness was a perfect fit and just as easy to install as the video shows as well. Caution: I did this by myself in a bout an hour but take note that this thing is made of some thick steel and is heavy; you MAY need another set of hands.

Chevrolet Equinox

2019 Equinox had the factory supplied plug mid way above the inside rear bumper. I plugged the unit in and did a test for voltage and it was 12+ volts. I did not install the two fuses that came with it. The side rear fuse box from the factory didn't have the female connections too insert them. Hooked my utility trailer up and/or small fishing boat and everything works perfect. One year later all is well!! Not really sure you need the two fuses that came with. So far I don't.


Very good service!


Works Great!

2019 Chevrolet Equinox

Thank you etrailer for providing me the product and service I was looking for. Your on-line video helped me choose the best option for me. Great communication and follow up from the time my order was placed right up to the reminder survey.


Installed. Still need to connect trailer and verify it works but cant imagine there would be an issue.

2018 GMC Terrain

This was a very quick and easy installation. No fitment issues and is tucked away perfect. I highly recommend this product.

Show More Reviews

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

  • Where Do the Trailer Wiring Harness Relays Install on a 2018 GMC Terrain
    For wiring harness # 118285 you may not need the relays if they are already present on your 2018 GMC Terrain. If the wiring harness works then you can just hold on to them as spares. If it is not working then they will need to be installed. Locate the fuse panel at the back of your Terrain. It is behind a little access plate on the driver's side. There are 3 relays for tow package wiring in this box. K1, K2, and K3. The relays will need to go in the K1 and K3 locations. The K2 spot is...
    view full answer...
  • Troubleshooting 118285 For 2018 Chevy Equinox
    The T-One Vehicle Wiring Harness for Factory Tow Package part # 118285 for the 2018 Chevy Equinox is the wiring for a Chevy Equinox with factory tow package so you do want to make sure that the Equinox has a factory tow package first. You also want to make sure you have the relays of the wiring harness in the k2 and k3 locations in the fuse box. If the relays are in the correct location then you want to make sure the connector is seated fully with the wiring harness connector. Since the...
    view full answer...
  • Troubleshooting Driver Side Turn Signal On Trailer Not Working After Installing Tekonsha 118285
    It sounds like a fuse is either blown or missing from your 2019 Chevrolet Equinox which is causing the driver side turn signal on your trailer to not work with the Tekonsha T-one Connector # 118285 installed. The fuse in question is fuse F18 which is the driver side turn signal for the trailer wiring. This fuse is in the fuse compartment in the rear of your vehicle on the driver side panel.
    view full answer...
  • Troubleshooting No Power for Left Turn and Brake Lights for Trailer Connector on 2018 Chevy Equinox
    Since the issue you described is happening both with a trailer and with your magnetic tow lights I do think the culprit is a blown fuse or bad relay on the vehicle. I took a look at the online version of the owner's manual for your 2018 Chevy Equinox and there are a few different fuse panels so you want to make sure you are looking at the correct one. Inside the rear compartment fuse block, which is located behind the trim panel in the rear cargo area, there is a fuse in the F18 position...
    view full answer...
  • Tips To Disconnect The Tow Plug Connector On A 2018 GMC Terrain
    First, clean the connector # 118285 the best you can. Then you can go ahead and push them together as hard as you can. That will release some of the tension on the little tab. Then it may be a little easier to push in the tab and pull apart. If this doesn't work, repeat the process but you can use a hard edge like a flat head screwdriver or something to help get the tab to release.
    view full answer...
  • Is There Separate Fuses On A 2020 Chevy Equinox For The Trailer Light Functions
    Yes, on most newer vehicles they do have separate fuses for the different light functions. On page 306 in your owners manual it shows what fuses are for what functions for your trailer lights. The fuse panel is located in the cargo area of the vehicle on the drivers side. It is most likely the fuse but if the fuse is not blown then the wiring harness may have malfunctioned which doesn't happen very often with Tekonsha.
    view full answer...
  • Comparing the T-One Vehicle Wiring Harnesses for a 2018 GMC Terrain
    There are two types of trailer wiring harnesses for a 2018 GMC Terrain, the T-One Vehicle Wiring Harness part # 118285 which is for models with the factory tow package or the T-One Vehicle Wiring Harness part # 118764 which is for models without the factory tow package. It sounds like you have the one for models with the factory tow package but cannot find the factory plug so if that is the case then you will indeed need the other harness. I have attached a photo for you of the factory...
    view full answer...
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  • Troubleshooting T-One That Works Only on LED Light Trailer but Not with Incandescent Light Trailer
    Ralph, It sounds like the T-One Vehicle Wiring Harness for Factory Tow Package # 118285 is what you should be using for your 2019 GMC Terrain as it's designed for vehicles with a factory tow package. The # 118764, you mentioned, is designed for vehicles that do not have a factory tow package. LED lights draw only a fraction of the amperage when compared to incandescent lights, so what is very likely happening here is that you're dealing with a case of an insufficient or poor ground. A...
    view full answer...
  • How To Tell If a 2020 GMC Terrain Has the Factory Tow Package for Trailer Wiring
    In order to determine if a 2020 GMC Terrain has the factory tow package you will need to take a look in the rear fuse box on the driver side of the vehicle. In the fuse box there will be two locations you need to check, K2 and K3 which are for the trailer lights. These slots should be empty but what we are looking for is silver terminals inside each of the holes for the prongs on the relay. If there are silver terminals then you have the factory tow package but if not then you do not have...
    view full answer...
    Image 1 for
  • If There Is Tow Package Port On 2018 GMC Terrain Can You Use Trailer Wiring for Factory Tow Package
    In regards to a 2018 GMC Terrain, not all models with the tow package port will actually have the tow package wiring. In other words, the port may be present but the wires are not run from this to the fuse block therefore the port is inoperable even with the relays handy. The best way to tell is by calling the dealer but if there are actual contacts/terminals in the relay locations assume they are not already installed then you can use the factory tow package port on the rear. The T-One...
    view full answer...
  • Which Trailer Wiring Harness is Correct for a 2018 Chevrolet Equinox LT
    If you do not have the factory tow package on your 2018 Chevrolet Equinox LT then the correct trailer wiring harness for you is the T-One Vehicle Wiring Harness part # 118750, not the T-One Vehicle Wiring Harness part # 118285. The T-One Vehicle Wiring Harness part # 118285 is only for model equipped with the factory tow package. There will still be a plug for the latter harness but if you do not have the factory tow package then the circuits may not all be ran to the power distribution...
    view full answer...
  • Fit of Tekonsha 118285 Trailer Wring Harness on 2019 GMC Terrain
    As confirmed by Tekonsha, their # 118285 trailer wiring harness is a fit for 2018-2021 GMC Terrains equipped with the factory tow package. If your Terrain isn't equipped with the tow package, you'd instead need part # 118764. I've linked to install videos for both wiring harnesses.
    view full answer...
  • No Relays Found When Installing T-One Wiring for Factory Tow Package on 2019 GMC Terrain
    The T-One Vehicle Wiring Harness # 118285 that you referenced is supposed to be used if your 2019 GMC Terrain came with the factory tow package. If those fuse locations are empty then it sounds like you don't have the factory tow package and you need the T-One Vehicle Wiring Harness # 118764 instead which tees in behind your tail lights and doesn't require any relays. If your Terrain is supposed to have the tow package then you should have metal contacts where those relays install. Since...
    view full answer...
  • Which T-One Wiring Harness for a 2020 GMC Terrain
    Both Tekonsha T-One wiring harnesses will fit a 2020 GMC Terrain but it's based on whether or not you have the tow package on your vehicle as opposed to AWD vs FWD. With Factory Tow Package - # 118285 Without Factory Tow Package - # 118764 If you aren't sure if your Terrain has the tow package you can call your local GM dealer with your VIN and they can clarify this for you. I've also attached installation videos for both wiring harnesses on a 2020 Terrain for you to check out.
    view full answer...
    Image 1 for
  • Replacement Wiring Harness for a 2022 Chevy Equinox
    I am sorry to hear about that. Yes, we do have a replacement wiring harness for your 2022 Chevrolet Equinox. It is the Tekonsha T-One Vehicle Wiring Harness for Factory Tow Package item # 118285. This custom-fit T-One connector plugs into your vehicle's factory tow package wiring harness, which is located behind your rear bumper, on the driver's side. I have linked an installation video. To keep that harness from falling off and dragging down the road again I recommend the Mounting Bracket...
    view full answer...
    Image 1 for
  • Wiring Harness for a 2021 Chevy Equinox LT w/ out the Towing Package that is NOT the Premier Model
    There is a wiring harness for the non-premier 2021 Chevy Equinox's that did not come with the towing packages. It is the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector item # 118750. I linked an a close up picture of the connectors below so you can verify these match yours before purchasing.
    view full answer...
    Image 1 for
  • Trailer Hitch Recommendation for 2020 GMC Terrain
    You have chosen wisely because I highly recommend the Draw-Tite Trailer Hitch # 76419 for your 2020 GMC Terrain (non-diesel). The reason this is the best hitch for you is because it has the highest capacities at 4,500 lbs towing and 675 lbs tongue weight, which speaks to it's strength and durability, and because it is the only hitch rated for use with a weight distribution system, which is something people use regularly when towing. To add trailer wiring to power your trailer lights you...
    view full answer...
  • Trailer Wiring Recommendation for 2020 Chevy Equinox
    We have three options for trailer wiring that I would recommend for your 2020 Chevy Equinox. If you have the tow package already you'd want the part # 118285 which easily installs to the vehicle's factory wiring (see install video). If you do not have the tow package you'd want then the # 118759 for if you have a Premier model or part # 118750 if you do not have a Premier model.
    view full answer...
  • Recommended Trailer Wiring Harness For A 2022 Chevrolet Equinox
    When it comes to installing a trailer wiring harness on your 2022 Chevrolet Equinox The T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118750 is confirmed to fit your vehicle. The wiring has a simple plug and play installation that plugs behind the driver and passenger side tail lights. Then you will have to run the hot lead up to the car's battery. When the wiring harness is not in use I recommend The 4 Pole Mounting Bracket # 18144. This will keep your harness out...
    view full answer...
  • Recommended Wiring Harness For A 2019 Chevrolet Equinox
    When replacing your trailer wiring harness there are a few different options that you can have and I will explain below: If you do not have a factory tow package and its excluding the Premier The T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118750 will work for you. The harness plugs into your vehicle's wiring harness, which is located behind the driver's-side and passenger's-side tail lights. If you have the factory tow package The T-One Vehicle Wiring Harness for...
    view full answer...
  • Trailer Hitch and Wiring for a 2018 GMC Terrain 1.5 Liter
    Draw-Tite trailer hitch # 36642 is a fit for your 2018 GMC Terrain. But I recommend the Class III hitch # 76419 because it is a more stout hitch and the 2 inch receiver is compatible with many hitch accessories. For the Class III hitch, if you plan on doing some towing, I recommend etrailer ball mount kit # 989900. It comes with 2 ball mounts; one with a 3/4 inch rise or 2 inch drop and one with a 2-3/4 inch rise or 4 inch drop. It also includes a 1-7/8 inch ball, 2 inch ball, hitch pin...
    view full answer...
  • Which Trailer Wiring Harness for 2020 Chevy Equinox
    The wiring harness you meed will depend on whether or not you have the Premiers sub-model or not. For the Premier, you'd use # 118759 or # 118750 if it's not the Premier model. There's also a third less expensive possibility....if your Equinox has the factory tow package with the connector behind the bumper on the driver's side (see provided photo), you could use # 118285. The # 118494 you'd looked at is for an earlier model Equinox, and wouldn't work on your 2020 model.
    view full answer...
    Image 1 for
  • Recommended Wiring Harness For 2018 GMC Terrain Without Towing Package
    If you do not have a towing package you will not have the locations for the relays in the fuse box that come with the Curt T-connector wiring harness part # C56375 or the Tekonsha wiring harness part # 118285 because they are designed for the 2018 GMC Terrain with factory tow package. If you do not have the factory tow package you need the wiring harness with the converter box and in-line fuse holder part # 118764. Without the in-line fuse and converter box the wiring harness could potentially...
    view full answer...
  • Recommended Trailer Hitch for a 2020 GMC Terrain
    The trailer hitch that I recommend for a 2020 GMC Terrain is the Draw-Tite Max-Frame Trailer Hitch Receiver part # 76419 because it has a hidden design which means you won't see the bulky, unsightly cross tube from the rear of the vehicle so you won't take away from its aesthetics. I have attached a photo of this clean look for you as well. In addition to aesthetics, the hidden design makes for the best ground clearance. If you will be towing a trailer then you'll also need a trailer wiring...
    view full answer...
    Image 1 for

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Info for this part was:

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