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

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

Item # C89KR
Our Price: $113.96
You Save: $8.99
Custom Fit Vehicle Wiring

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Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring - no cutting, splicing or tapping required. Converter is made using SMT to ensure superior performance. 1-800-940-8924 to order CURT custom fit vehicle wiring part number C89KR or order online at Free expert support on all CURT products. Great prices and Fastest Shipping for Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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CURT Custom Fit Vehicle Wiring - C89KR

  • Trailer Hitch Wiring
  • 4 Flat
  • Converter
  • CURT

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring - no cutting, splicing or tapping required. Converter is made using SMT to ensure superior performance.


  • 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 behind tail lights
    • Plug in T-connector
  • Includes a tail light converter to ensure that your vehicle's wiring matches that of your trailer
  • Constructed using surface-mount technology (SMT) for consistent, reliable performance
    • Maximizes trailer light yield and intensity while producing minimal heat
    • Ensures superior operation in rough road conditions
  • Comes with dust cap for 4-way flat connector
  • Limited 1-year warranty


This custom-fit T-connector plugs into your vehicle's wiring harness.

Once installation is complete, the 4-way connector will be stowed in a secure location.

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.

Tail Light Converter with Surface-Mount Technology

A tail light converter is built into this T-connector. Because most trailers run on a two-wire system - wherein the brake and turn signals are carried on one wire - the separate brake and turn signals from your vehicle's three-wire system need to be combined so they are compatible with the wiring system of the trailer. This converter combines the brake and turn signal functions of your automobile so that they run on one wire to properly activate your trailer's tail lights. Note: This will not affect how the tail lights on your vehicle operate.

Curt builds each tail light converter using surface-mount technology (SMT). This method of construction involves soldering electronic components directly to the surface of a printed circuit board. SMT eliminates the need for leads, which are used in older through-hole technology. The result is a circuit board that is smaller yet provides more routing area and that offers superior performance, reliability and durability.

Curt SMT Circuit Boards

Circuit boards constructed using SMT have been shown to perform better under rough conditions with excessive vibration than those made using the through-hole method. And where would vibration be more likely to occur than in towing applications? Curt converters also produce less heat, leading to increased durability and longer life. In addition, lower levels of resistance ensure better performance, especially for parts that operate at higher frequencies.

Each Curt circuit board is made using high-quality components that are pieced together in the most technologically savvy fashion, leading to greater predictability and reliability in functioning.

56442 CURT T-Connector - Surface Mount Technology - 4 Wire

Compare to Tekonsha TK49FR

Installation Details C89KR Installation instructions

This Product Fits The Following Vehicles

Customer Satisfaction Score:

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C89KR

Average Customer Rating:  4.7 out of 5 stars   (119 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring - no cutting, splicing or tapping required. Converter is made using SMT to ensure superior performance.


Okay, this was not a 5 minute install, but you knew that before ordering....right?

I should have gotten my SUV up in the air a little better than I did, but I managed to squeeze in where I needed to. I only lifted the back using ramps.

I followed the instructions and example videos and used a trick or two to get this installed (I used a 4' long fiberglass rod to fish up the cable, anything similar would work - fishing pole parts, wood dowel, etc.).

Like I said, wasn't 5 minutes, but in the end I know it was done right and should last. I bought a $4 tester from Harbor Freight and verified the connector was setup correctly (4 connector trailer wiring tester).

I just tested it again, after several months of no use, it's still perfect.

I installed the hitch receiver myself, and this wiring harness myself, and everything is perfect.

Tip, for the hitch receiver put the provided bolts in part way on one side, then use a tie-down strap to hold up that end, while you bolt up the other side. Then you just bolt up the side the tie-down was holding for you and you're 90% done. Hey...if you're on your own you make it work!



One year out now and the hitch and the wiring harness are rock solid. I will be buying a couple of mountain bikes pretty soon, sure glad Ive got this hitch. I also used it to haul a rented aerator back and forth from a local rental place. All the trailer lights worked perfectly!

Etrailer Expert

Mike L.


@Mike Awesome! I've linked you to an article with lots of advice on choosing a bike rack that will meet your needs!


The wiring harness has not worked properly from the get go. Sometimes the both the running lights are on, sometimes not, sometimes only one light. Brake lights don't always work. Sometimes they do. The left turn signal has never really worked. The right works though.

When the running lights are working they don't turn off even when the car is off (and the car's lights are off). The only way to get them off is to unplug the trailer. So if I leave the trailer hooked up overnight I need to remember to unplug the lights (and remember to plug it back in the next morning).

I wouldn't recommend this harness. It has not been reliable for me. It might seem like a good idea to not have to splice into your car's wiring but it would be simpler and easier to just splice the wires in.

Etrailer Expert

Jenny N.


There is a lot going on with this harness. I have a few trouble shooting tips that I would like to have you try. The first would be to check the ground and make sure that it is a good ground that it connected to bare metal on the vehicle. The second would be to take out the fuse in the inline fine connection for 30 second to 1 minute and then re-insert it. If the harness is still experiencing problems then it might need to be replaced.


This harness worked perfectly for the 2020 Hyundai Tuscon! The instructions provided by made it easy for a novice like myself to have the confidence to install and it turned out great! I'd recommend them to anyone!



The wire harness hasnt failed. Its been perfect since it was installed. The install instructions provided by etrailer were perfect for the install. It made the install much easier.

Etrailer Expert

Mike L.


@Paul We're happy to hear they were helpful!

2019 Hyundai Tucson

The instructions say the installation is EASY, Far from it!!
You must run a heavy power wire from the battery under the hood to the control module under the rear bumper. This is extremely tough as there is literally nothing on the underside of the car to hang a wire from. I finally had to disassemble and remove the panels that cover the fuel and electrical and run the wire under there. Hope it never shorts out on the fuel line!! Next the control box is mounted with double sticky tape and the kit supplied tape was old and dried out and turning to dust. So now I need to go to a hardware store but the whole back end of the car is gutted for this install, and can't be driven. Not Happy in Arizona.
And the instructions are vague, with pictures that mislead.

Etrailer Expert

Jenny N.


It can be tough to route the power wire from the battery to the harness. We have created a FAQ that can help that you can see in the link below. For the double sided tape what I will do is have our Customer Service team reach out to you. You can use double sided sticky tape to install. You just want to make sure it will not be bouncing around as this will shorten the life of the harness.

Kia Soul

This was a good kit overall. Was pretty tricky for me to find the right place to mount it for my 2020 Kia Soul but overall it worked great in the end.

Kia Soul

I have a 2022 KIA Soul that I recently installed a class one hitch on. I purchased a Curt exact fit hitch for it, along with this wiring harness. It fit perfectly. Due to the electronics within the car, and the LED lights, an additional “brain box” was needed to properly lower my pop up camper lights. The only minor annoyance was having to run a direct wire w fuse holder to my battery from the rear of the vehicle. That took about another hour. Works perfect. And great service from etrailer. Thank you.

2020 Hyundai Tucson

Fast shipping and easy installation. The etrailer installation videos make the installation simple. I highly recommend etrailer


Excellent so far. Install was tricker than expected and I’m not a novice. The video is extremely helpful, but they do the “and then just…” thing at a couple of points where more detail/step by step instructions would be really helpful. Great products though, as usual. I would purchase again, just know that you’ll need to do some of your own thinking and problem solving on the install. If you’re not comfortable doing that, go to a shop.


I still have not installed because the directions tell me to connect a ground to a screw that does not exist. I have to drill a hole in the painted surface behind the taillight to attach a ground.

Etrailer Expert

Katrina B.


Can you please confirm if you are referring to the tapping screw? If so, we can either send you the missing screw or you can take a trip to the hardware store. If not, please let me know what screw you are talking about.


This product helps me tow at least twice a week for the majority of the day. Absolutely no complaints. Super easy to install with very straightforward instructions! In fact I love this product so much I’m thinking of installing one on my other vehicle.


works well no problems at all


Great product


Works well. No problems. I'm happy with it.

2021 Kia Soul

It's all already installed...


Have not installed products at this time, but all look very good. I’ve used Curt Towing Products in the past and the quality has always been 1 class. First time I’ve used etrailer, website is user friendly, order arrived a day early, and was packaged well. Price for items ordered was very reasonable. Called customer support when ordered arrived to verify some information, and support was excellent!!!

So far so good!!!….. I would recommend!!!


Great product! I received my order within a few days of ordering it. The install was very simple. The longest portion of the install is routing the power wire from the battery to the rear of the vehicle. I used a "fish tape" to help with the task and followed the brake lines for most of the route. The instructions were easy to read and very simple to follow. The connectors fit perfect and within an hour (plenty of water breaks because the of the Oklahoma heat), I had it installed. Works perfect! I would suggest that you have a few more zip ties on hand to helps secure the power wire.

Great job! Perfect company (as usual)!!! Thanks for the quick shipping!



Great product. No issues at all and is still working perfect.


I followed the advice and then video and went and got the kind of connectors that include heat shrink on their ends. Just let me do a perfect job of installing this hardware. But I do highly recommend you look for the YouTube videos that etrailer did on the subject.


Great kit that is easy to install.


Perfect fit. Works great on my 2021 Kia Seltos.

Hyundai Tucson

Wiring harness was easy to install per the instructions and every part appears to be high quality. Wire lengths provided were much more than enough for the Tucson it was installed in, with several feet to spare for each wire.



Still no issues. Wiring harness continues to function properly.


Great Product Fast Shipping
Fit 2033
Kia Seltos perfect!!!

2020 Hyundai Tucson

Easy install, love how there’s access to install instructions!

2019 Hyundai Tucson

I liked the wiring harnesses for easy connection the lights. And even though this needed to be connected to the Positive terminal it was alright.

My only complaint is the module with all of the wiring needs a more secure method of attachment. Mounting tape provided was not sufficient. I ended up making a harness with Pipe Straps.

2021 Kia Seltos

This is a great quality product. It was a perfect match for my vehicle. The installer said it was easy to install.

2019 Hyundai Tucson

This kit is great! It is designed to take all of the guesswork out of wiring trailer lights, and it delivers. Watch the video and you will be a pro at installing this system. I can't believe how easy eTrailer makes this somewhat mystical installation such a breeze. What a great Company!

Show More Reviews

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

  • Trailer Wiring Kit Compatible With 2021 Kia Soul Without LED Taillights
    The Curt Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C89KR is a confirmed fit for both 2020 and 2021 Kia Soul with or without LED taillights.
    view full answer...
    Image 1 for
  • Can 12V Feed For Powered Taillight Converter Be Attached to Power Source Other Than the Battery
    When installing a powered taillight converter like # C89KR, Curt doesn't recommend attaching that 12V power feed to anything other than the positive battery terminal, so I can't recommend anything that would contradict the manufacturer's advice. Drawing the power directly from the battery serves to isolate the tow vehicle's sensitive electronics from any short circuits that might occur in the trailer wiring. Connecting the converter's power feed anywhere other than the battery or where...
    view full answer...
  • Recommended Trailer Hitch Receiver For A 2024 Kia Soul
    Curt is currently the only one with a hitch for a 2024 Kia Soul, but their hitch only fits models with a 2.0L engine. The Curt Trailer Hitch Receiver # C89KR is a simple bolt-on installation and comes with a 1-1/4" receiver opening to haul around your accessories. If you have the 1.6L engine you would not be able to use this hitch and there are currently no options available. If you also want to add lights to a cargo carrier or bike rack for better visibility on the road then I recommend...
    view full answer...
  • 4-Way Trailer Wiring For 2024 Kia Soul
    The correct 4-way trailer wiring for your 2024 Kia Soul is the following from Curt: - Curt T-Connector Vehicle Wiring Harness # C89KR
    view full answer...
  • Where Does the Converter Box for Curt Trailer Wiring Harness On a 2020 Kia Seltos Install
    The Curt T-Connector Vehicle Wiring Harness part # C89KR which is a fit for a 2020 Kia Seltos contains a converter box which will mount behind the taillights on the outside of the vehicle. The pigtail with green wire will then be run behind the bumper cover in front of the body panel to the other side.
    view full answer...
  • Correct Curt Trailer Wiring Harness for a 2023 Kia Seltos
    I was able to confirm that the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # C89KR is correct for a 2023 Kia Seltos (All Models).
    view full answer...
  • Plug In Wiring Harness For A 2024 Kia Seltos
    Yes there is! For a plug-in 4-way wiring harness for your 2024 Kia Seltos we have the Curt T-Connector # C89KR. I just checked with the manufacturer and confirmed that this will fit all models of the 2024 Kia Seltos. It will plug in behind the tail lights on the driver and passenger side. A wire will need to be run to the battery to power the converter box. You will find one of our install videos for the Curt # C89KR linked below.
    view full answer...
  • Where Does The Curt Trailer Hitch Receiver # C89KR Attach To The Factory Wiring On 2021 Kia Seltos?
    The Curt T-Connector Vehicle Wiring Harness # C89KR for your 2021 Kia Seltos connects to the back of both the drivers side and passenger side tail lights. You will need to run the green wire with the plugs up to the passenger side tail light. I have linked a installation video below which shows the installation performed on a similar Hyundai Tucson since they are on the same chassis. They do not show the removal of the passenger tail light as it is similar to the removal of the drivers...
    view full answer...
  • Trailer Wiring Harness For 2020 Kia Soul With LED Lights
    According to Curt the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # C89KR fit all models of the 2020 Kia Soul even with LED lights. This harness will give you a 4-pole flat at the rear of the Kia Soul. I have attached the installation instructions for your reference.
    view full answer...
  • Trailer Hitch Wiring That Fits 2021 Kia Seltos
    While we do have trailer hitch wiring for your 2021 Kia Seltos, wiring is vehicle-specific so will only fit the cars and trucks it is designed for. So the wiring for a Ford Focus won't fit your Seltos; instead, for a 4-way on your Seltos, here is exactly what you will need: - Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C89KR
    view full answer...
  • How Can I Tell If My Trailer Module Needs To Be Replaced
    It certainly sounds like you are in need of a new module. It is not unheard of for them to go bad. Generally when it works fine for a long period of time, then stops working, this is a sure sign that it needs to be replaced. We would want to verify that the new fuse you used is a 10 amp, and that you are 100% sure that you have a good ground free of any rust, paint or corrosion. Other than that, there is really nothing else that could cause this issue. The module is wired directly to...
    view full answer...
  • Trailer Wiring Harness For 2021 Hyundai Tucson Sport
    The good news is I have a solution for you! The only one you need is the Curt T-Connector # C89KR, which is our part number for their harness #56442. It sounds like you've been bombarded with lots of results of similar trailer wiring products. I can certainly understand why it might be both overwhelming and confusing to know which one is best. You listed three t-connector harnesses and one tail-light converter in your list, and two of them are the same part, just with different identifying...
    view full answer...
  • Installation Instructions for Trailer Wiring Harness for 2021 Kia Seltos
    There are instructions on the product page for the Curt Wiring Harness with 4-Pole Flat Trailer Connector # C89KR, but I've also linked them on this answer for you. This is a fairly simple installation that just requires teeing into the vehicle lights with the included wiring, so it's really quite simple once you access the tail lights of your 2021 Kia Seltos. Unfortunately that part we don't have access to and we haven't performed this installation since it's a relatively new model for...
    view full answer...
  • Recommended Wiring Harness For A 2024 Kia Soul Without LED Lights
    You are correct that both the Curt # C89KR and Tekonsha # 118813 are going to fit your 2024 Kia Soul without LED lights. Both products are going to be virtually identical. You are looking at two different manufacturers version of the same custom fit wiring harness. If it were my car, I would go with the Tekonsha # 118813. The Tekonsha products are known to be superior as far as durability and longevity, so this is what I recommend.
    view full answer...
  • What Wiring Harness Works with My LED Taillights on My 2021 Hyundai Tucson?
    If you want to hook up a trailer with LED taillights to your 2022 Hyundai Tucson, I confirmed with Curt that the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C89KR will be compatible with LED-style lights. If you need help with installing the harness, I went ahead and linked a video that walks you through the process. If you need a hitch as well, I recommend the Curt Hitch - 2" # C13240. Not only does the 2-inch receiver allow compatibility with many accessories,...
    view full answer...
  • Trailer Wiring Harness Recommendation for 2021 Hyundai Tucson with LED Taillights
    The Curt trailer wiring harness part # C89KR is a fit for your 2021 Hyundai Tucson with LED taillights but I would actually recommend the Tekonsha part # 118812 as it has a more reliable converter box.
    view full answer...
  • What Tools are Needed to Install a Curt Trailer Hitch on a 2022 Kia Soul
    Installing the Curt Trailer Hitch Receiver # C67FR on your 2022 Kia Soul is something that I am confident that a moderate DIY person can handle. I have attached a picture from the installation instructions that shows the tools that you will need to accomplish this install. If you will be towing a trailer, the Curt T-Connector Vehicle Wiring Harness # C89KR will provide a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights.
    view full answer...
    Image 1 for
  • Recommended Trailer Hitch and Wiring Harness for a 2021 Hyundai Tucson
    I was able to confirm with Curt and the Curt Trailer Hitch Receiver part # C13240 has been carried over as a fit for a 2021 Hyundai Tucson. In regards to the trailer wiring, you can use the Curt T-Connector Vehicle Wiring Harness part # C89KR. These are both great bolt-on/plug-in play options that will get you setup and towing in no time. In order to complete your setup, I'd add the etrailer Ball Mount Kit part # 989900.
    view full answer...
  • Install Instructions for Trailer Wiring That Fits 2020 Kia Soul
    You have the universal Curt trailer wiring harness that fits your 2020 Kia Soul with part # C59236 which we do have the easier to install kit part # C89KR which would have been my recommendation for you. But the type of taillights your 2020 Kia Soul has is separate so that would be the set of instructions you should follow in the install instructions that I have attached to this page.
    view full answer...
  • Recommended Trailer Hitch Receiver and 4-Way Flat Wiring Harness For a 2020 Kia Soul LX
    We have a wiring harness that will fit both the LED vs non-LED tail lights. It is the Curt Vehicle Wiring Harness # C89KR for your Kia. I recommend the Curt Trailer Hitch item # C67FR as the best receiver option. This is the only receiver we offer that has the larger 2" receiver. The larger receiver gives you more options for ball mounts when towing and is compatible with more hitch mounted accessories.
    view full answer...
  • Can Hitch for 2020 Kia Soul Transport 300 lb Mobility Scooter
    The problem with hitch adapters is they cut the capacity of the hitch they are installed in by 50 percent and for a lighter duty vehicle like what you have you just don't have the tongue capacity for that. Especially since you want to carry 300 lbs in the carrier. You'd have to use the Curt hitch # C67FR that fits your 2020 Kia Soul to tow a smaller trailer. For wiring you'd then need the part # C89KR.
    view full answer...
  • Hitch Confirmed to Fit a 2022 Kia Seltos
    Yes, the Curt Trailer Hitch Receiver # C65FR is confirmed to fit all models of the 2022 Kia Seltos. This hitch is made in the USA, has a bolt-on, no-drill installation and will provide you with a Class I, 1-1/4" hitch for using hitch mounted accessories such as bike racks, cargo carriers and ball mounts. If you plan to do any towing you will also want to pick up the Curt T-Connector Vehicle Wiring Harness # C89KR which will provide a 4-way flat connector to power your trailers signal lights.
    view full answer...
  • Wiring Harness for a 2022 Kia Seltos
    I have a great wiring harness for your 2022 Kia Seltos and it is made by the best wiring company in the business Curt. It is the Curt Wiring Harness with 4-Pole Flat Trailer Connector item # C89KR. This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located in your rear cargo area, behind the driver's-side and passenger's-side tail lights. The powered ModuLite reduces strain on your Kia's wiring system by providing power directly from your battery. For a...
    view full answer...
  • How Difficult Is It To Install The Draw-Tite Hitch On A 2022 Kia Seltos?
    We rate the install difficulty for the Draw-Tite # DT65GR on your 2022 Kia Seltos as a 5 out of 10, so it isn't overly difficult. Especially since you have done one before. There will be no drilling needed, but there is very minor trimming of a panel to finish the install and I included an image from the instructions showing what this entails. And again, it's very minor. As to the wiring, I recommend going with the Curt Wiring Harness # C89KR. Though one wire will need to be run up to...
    view full answer...
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Do you have a question about this Custom Fit Vehicle Wiring?

Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Jameson C
Expert Research:
Jameson C
Employee Lindsey S
Edited by:
Lindsey S
Employee Kathleen M
Installed by:
Kathleen M
Employee Chris R
Video Edited:
Chris R
Employee Wilson B
Updated by:
Wilson B
Employee Noah M
Updated by:
Noah M
Employee Jonathan Y
Video by:
Jonathan Y
Employee Conner L
Test Fit:
Conner L
Employee Kristina F
Written by:
Kristina F

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