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  1. Custom Fit Vehicle Wiring
  2. Kia
  3. Sportage
  4. 2018
  5. CURT
FITS 2018 Kia Sportage
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 # C56321
Our Price: $72.09
You Save: 47%
Custom Fit Vehicle Wiring
Confirmed to Fit
2018 Kia Sportage

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The best technical support and full custom fit vehicle wiring installation instructions. Great price Sportage custom fit vehicle wiring and expert service. Kia Sportage, 2018 custom fit vehicle wiring by CURT are available from For expert service call 1-800-940-8924 to order your Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part number C56321, or order online at
  • All Info
  • Reviews (108)
  • Q & A (0)
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  • Why etrailer?

2018 Kia Sportage - Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • Powered Converter
  • CURT

Quickly and easily install a 4-way trailer connector on your Kia Sportage with this custom harness. T-connector plugs directly into existing wiring. Powered converter reduces strain on wiring system and 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
    • Locate connection points behind driver's-side tail light and rear bumper
    • Plug in T-connector
    • Run hot lead to car battery
  • Includes a tail light converter to ensure that your vehicle's wiring matches that of your trailer
    • Powered module connects directly to battery to avoid overloading vehicle's electrical system
  • 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


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


This custom-fit T-connector plugs into your vehicle's wiring harness, which is located behind your driver's-side tail light and behind your rear bumper on the driver's side. You will have to remove the plastic cover behind your bumper, trunk floor coverings, rear scuff panel, trim panel, and tail lights to access this harness. Once you've plugged in the T-connector, run the hot lead up to your car battery. Connect the lead to the included fuse holder, and then connect the fuse holder to the positive terminal on your battery.

Once installation is complete, the 4-way connector will be stowed in an out-of-the-way location within your cargo area.

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.

Powered Tail Light Converter with Surface-Mount Technology

A tail light converter is built into this T-connector. This converter is a circuit-protected, battery-powered unit that bypasses the electrical routes that are used by a basic wiring harness. As a result, there is virtually no draw on your tail light circuits.

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.

56321 Curt T-Connector Kia Sportage Wiring Harness with 4 Pole Trailer Connector

Installation Details C56321 Installation instructions

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C56321

Average Customer Rating:  4.9 out of 5 stars   (108 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. Powered converter reduces strain on wiring system and is made using SMT to ensure superior performance.


The wiring harness worked perfectly and I've been using my Sportage to pull trailers all over town. Working with was quick and easy. Thanks.


This wiring harness is the perfect compliment to my Curt hitch receiver. I love the length of the cable and it stays tucked away into the spare tire compartment in the rear portion of the vehicle.


Easy install, very complete & professional kit with effective instructions. The video link mirrored the instruction and was informative on a few of the finer details. 2 hour install for me, that included letting the black silicone setup. Running the power wire to the battery is a pain in thebutt without a lift, but very doable.

After one year of service, its still performing as when new. Highly recommended product.
George - 06/14/2022


Amazing product. Very easy to follow the step by step video on everything easily plugs in and is out of the way. No cutting into the existing harness. It's amazing


Super easy to install, I didn't run into any issues at all. The directions were straight forward and I do love the fact that its all direct plug. I have had this wiring harness for a year now and its still running strong. I am very please with the product.


The wiring harness fit perfectly and the direct plug adapters made the job simple and quick.


After purchasing a new Kia Sportge last year from on the sales lot I was unable to obtain a hitch or light hook-up from them. I was able to get a hitch installed locally--but still no luck on lights--imagine Kia not having access to these services!! So I went on line & easily found the website. I had no problem finding the exact kit for my year & model Kia--it was shipped promptly & I had the same business install it that did the hitch. Thank you etrailer!! (this review from a "senior" female not too computer or vehicle savvy!!)

No problems- wiring kit was installed by a local trailer business & has performed with no issues. Thanks for the follow-up
Barbara - 03/13/2019


I received the wrong part from different company and needed the right one in a rush, Jesse M. Made it happen Thanks!!

2020 KiaSportage

Received the package today. In these days of mediocre or no service, I was extremely happy with the speed of the order. Just hours after placing the order I was notified it had shipped. The map showing where it came from and the destination was a nice touch. Good quality product that I will install on my 2020 Kia Sportage. Thank You

Plug in broke while I was on the road. I had to buy a new harness at a parts store and rewire it myself in order to continue on my way and have lights on my tear trailer
Bill S - 04/24/2021


does not fit 2023

this fits a 2017-2022 Kia Sportage currently.
-- Etrailer Expert Sierra K - 07/15/2022


Great hitch,fit perfectly.


Wiring harness fit perfect, would buy again. Easy install, great product.

2017 KiaSportage

I successfully installed the Curt wiring harness a couple days ago. The etrailer videos and instructions were excellent and invaluable to me. I did find it challenging to fish the 10 gauge power wire from the rear bumper area to the battery. etrailer installation photos were excellent also. I'm waiting for the Curt connector tester I ordered yesterday to check out the Curt wiring system before I rent any trailers.


easy to install, works perfectly on my 2020 Kia Sportage


I needed to wire my Kia Sportage for a trailer. The dealership wanted to charge me 250 bucks for the wiring harness. I checked online to see how hard it would be. etrailer had a video showing their product and its EXACT installation. Part numbers, How to on my vehicle. And 65 bucks. It was EXACTLY as they showed. Down to every screw.


Spoke with Shawn B on the phone and within just a few seconds had clarification on the wiring I needed. She was awesome, friendly and courteous. The wiring harness fits perfectly, easily wired and was easy to complete. A plug and play harness. I'm very pleased with my purchase, the cost was less than at other places and there was free shipping! What else do you need?!

2017 KiaSportage

Hitch installation was easy. The wiring was more challenging but no splicing and the instructions guided us through the whole process. Hitch and lights both work great and have had no problems at all since installation.


The wire harness I purchased worked out great and was easy to install, the price was also great. Thank you.

2021 KiaSportage

Curt T connector wiring kit arrived with the hitch(gave review for hitch already). Watch and followed video for installing wiring kit. Had no problems, great instructions. I went extra slow because I am not much of a wiring guy.


Works great!

2017 KiaSportage

I've purchased from etrailer before and never disappointed. Great product and great company to do business with. Never had an issue towing [rental] trailers etc. installation was smooth if u follow the instructions explicitly

2019 KiaSportage

Tried to edit my previous review, but could not find it. Just had to write another saying etrailer fixed my product issues, Although they didnt email me letting me know they did. Was left in the dark as far as if my hitch was going to be replaced, but in the end a new one showed up today.


Nothing is better than a plug and play system. This wiring harness was no exception. It took maybe 45 minutes to install and worked. No issues.


put trailer together but one air hindge wasent good so requested a replacement and they were very respectful, we recieved it in a timely manner and are satiisfied .. would order from this place again.


great and fast service , great product . helped me out with harness that i needed for my kia and tow hitch easy and the price is right thanks

Show More Reviews

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

  • Recommended Trailer Wiring Harness for a 2022 Kia Sportage
    The trailer wiring harness that I recommend for a 2022 Kia Sportage is the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # C56321. This harness is a direct plug-in-play fit with no cutting or splicing required. It provides a 4-pole connection which is the most common type and used on most trailers without brakes.
    view full answer...
  • Fuse Size in Curt Wiring Harness For Kia Sportage
    A 10-amp fuse is used in the Curt wiring harness that fits your Kia Sportage, the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56321.
    view full answer...
  • Why Does Trailer Wiring for 2019 Kia Sportage Wire up to Vehicle Battery
    All of the trailer wiring harnesses for your 2019 Kia Sportage require running the power wire up to the vehicle battery. While this makes for a more involved install it does allow your vehicle to have more circuit protection and you'd never have to worry about a trailer wiring short causing damage to your vehicle wiring. This is because the harness draws power from the vehicle battery and not the vehicle taillight circuits.
    view full answer...
  • Does Curt Trailer Wiring for 2022 Kia Sportage Affect Reverse Camera
    The Curt trailer wiring harness part # C56321 that fits your 2022 Kia Sportage does not affect the reverse camera at all. It would function exactly the same as it is now.
    view full answer...
  • Comparing Tekonsha T-One and Curt T-Connector Wiring Harnesses for a 2018 Kia Sportage
    The T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # 118698 is what I recommend for a 2018 Kia Sportage. In comparison to the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # C56321, the T-One has a different converter box which is easier to secure and more reliable (better potting). It also has an integrated dust cap as opposed to separate on the T-Connector which can easily be lost.
    view full answer...
  • Are There Any Replacement Parts for the Curt T-Connector Wiring for a 2017 Kia Sportage
    If the powered module that comes on the Curt T-Connector # C56321 shorted out and now your trailer lights are staying on constantly then you will need to replace your wiring kit as there are no replacement circuit boards or modules. You can however use the Curt Upgraded Circuit Protected Powered Tail Light Converter # C56496 and just splice it in behind the converter box. If you'd rather go with a whole new kit then I recommend using the Tekonsha T-One # 118698 because we have found the...
    view full answer...
  • Curt Class III Trailer Hitch that Fits 2020 Kia Sportage
    Curt has a similar Class III hitch that fits your 2020 Kia Sportage with the # C13281 but the # 13526 that you referenced is not a fit and would not work. I attached an install video for this on a similar 2020 Sportage as yours for you to check out. For trailer wiring you could then use the part # C56321 this is very easy to install and also very reliable.
    view full answer...
  • Will the Curt Trailer Hitch Receiver # C12158 Fit Both the 2017 and 2020 Kia Sportage?
    The Curt Trailer Hitch Receiver # C12158 is confirmed to fit all trim levels of the 2017-2021 Kia Sportage. If you are transferring this hitch from a different vehicle I recommend using new hardware. The Replacement Hardware Kit for Trailer Hitches # RHK will allow you to order a new set of hardware specific to your hitch. Both the Curt T-Connector Vehicle Wiring Harness # C56321 and Tekonsha T-One Vehicle Wiring Harness # 118698 will also fit the 2020 Sportage if you are needing to transfer...
    view full answer...
  • Recommended Trailer Hitch for a 2020 Kia Sportage
    The trailer hitch I recommend for a 2020 Kia Sportage is the etrailer Hitch part # e72TR. The etrailer Hitch offers a complete bolt-on installation with no cutting/drilling or special tools involved therefore no permanent modifications are required. This is certainly something you can install at home, in your driveway without much effort as it only takes most on average around forty minutes or so. This Hitch has a concealed cross tube so the only part that is visible will be the receiver...
    view full answer...
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  • Parts Needed for 2021 Kia Sportage to Tow Trailer With Electric Brakes
    The Curt T-Connector Vehicle Wiring Harness # C56321 will only allow you to power your trailer's signal lights. If you want to tow a trailer with electric brakes using your 2021 Kia Sportage you will need to add a 7-way and a brake controller in addition to the 4-way connection. The first thing you need to do is add the 4-way. I recommend the Tekonsha # 118698 over the Curt since we have found Tekonsha to be the most reliable when it comes to wiring. Once this is installed you will need...
    view full answer...

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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jameson C
Expert Research:
Jameson C
Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video Edited:
Chris R
Employee Dustin K
Video by:
Dustin K
Employee Cole B
Installed by:
Cole B
Employee Chelsea B
Written by:
Chelsea B
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Isabelle B
Updated by:
Isabelle B
Employee Conner L
Test Fit:
Conner L
Employee Bradley B
Test Fit:
Bradley B

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