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Wiring a trailer doesn’t have to mean tapping into factory wires. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector plugs directly into the tail light connectors, giving you a clean and simple setup. No splicing or guesswork—just plug it in behind each tail light and it’s ready to go.
This harness uses a powered converter that draws power straight from the vehicle battery instead of the tail light circuits. That keeps the vehicle wiring protected from overload while still sending full power to the trailer lights. It’s designed for vehicles without a factory tow package, so you get reliable trailer lighting without stressing the stock wiring.
Once installed, you get a standard 4-flat trailer connector that runs your trailer’s stop, turn, and tail lights. It’s the simplest way to make sure your trailer mirrors your vehicle’s lighting for safe and legal towing. You can also add a 7-way adapter later if you need more functions like power or brakes.
The harness routes behind the tail light assemblies for a hidden, tidy install that keeps everything out of sight and protected from damage. With factory-style connectors and weather-sealed ends, it’s built for long-term reliability under all kinds of driving conditions.
Customer Satisfaction Score:
90% were satisfied with this product
10% of customers were not satisfied
Ratings & Reviews
With the help of the etrailer install video, the installation of this product was relatively easy. One thing that I usually do with wiring harnesses is to first wrap them with quality electrical tape to provide additional abrasion resistance. Also make sure to use enough wire ties to secure the harness and keep it from being too loose in places.
I gave the product a 4 star review because the double stick tape for the module is not very tacky and losses adhesion quick. I had to find another method to keep it secure. Otherwise the harness works for the purpose as designed and I am satisfied.
The f/irst unit did not work properly for the passenger side, replacement worked perfectly. 2014 Kia Sorento i4. The instructions and the video were both very incorrect for this vehicle. The installation for the power cable is the only thing you have to follow and the video shows where I ran the cable, before I viewed the video. This unit can be installed by removing the 2 tail lights if the power cable is already ran, otherwise you only have to remove 5 plastic screw plugs to remove the cover underneath the driver side of the vehicle to run the wires. Much easier if you put the rear on ramps or jack it up. The unit plugs into the drivers tail light and all of the other cables, after the black power cable is connected and you screw in the ground cable, simply drop down and you can reach them from the bottom, even with large hands. You can shine a light underneath the vehicle if you are in a poorly lit area and can look down the tail light holes to see the opening where you will reach in and pull the wires out underneath the vehicle. It is easier with the cover removed, but I did not need to do that for the re-install nor did I do it at all for the passenger side either time. I did not have to remove any of the interior, nor mess with the grommet behind the driver side interior panel. I do not have any idea, even after repeatedly viewing the video (which is much more informative for a non-mechanic than the instructions) and re-reading the instructions. Also note, this kit is plug-n-play. No blue splicing connectors like the video shows on the same page. You unplug the tail light from the car, plug the controller in (don't unwrap the driver side wires either) to the car and the other end into the tail light. This is how simple it is. Took me 1 hour to install it the first time and 45 minutes to run the power cable because I had to figure out a safe route, which turned out to be along the round wheel panel an then the same path the video shows going forward to the battery. It took about 5 minutes to do the re-install now that I knew nothing had to be removed from the vehicle except for the 2 tail lights.
5 stars for simple installation. Wish the instructions were made for someone who has never done an install before and again I have no idea what they wanted to run through the grommet. I suppose maybe they want the passenger green wire ran inside the car instead of across the hitch??? I was not able to make out what the instructions wanted- too vague. The video is not for this kit and lacked the grommet area along with how to begin the black power cable – only shows from the front of the rear wheel to the battery and has no specific instructions on how to route it.
Oh, it also tells to disconnect the existing cables, if any, going through the grommet and to be careful not to break the plastic tabs on the connector. I was not able to figure out how to unplug the connector, but luckily none of that that was needed. If it is needed, I was not able to make out what they wanted me to do with the grommet section.
In case it helps, I would do it this way:
1) Remove the 2 taillights and place them in a safe place.
2) Connect the black power cable, run it to the battery, leaving about a foot sticking out of the tail light hole. Ensure you can always get to the but connector in the future.
3) Watch the video and ensure the ground wire and screw are EXACTLY where they tell you in the video. You must screw through 2 layers of metal and be in the area where the tail light will go back in place all of the way.
4) Do not unwrap the drive side wiring. Unwrap the other cables and drop them down the hole, reach in the whole, or remove the cover, and pull the wires underneath the vehicle.
5) Stick the unit to the same place the video shows.
6) Plug in the driver side taillight and screw it back to the vehicle.
7) Run the green wire to the passenger side. Use a pull wire or bungy cord down the hole and pull up the green wire. Connect it to the tail light and screw the light back on the vehicle.
8) The video shows large wire ties for the wiring, but there is only ONE, use it for the green wire and the 4 connector as the video shows.
I had this installed by a mechanic. The installation is difficult if you don't have a lift and all the tools. However, once installed, the product works great. I highly recommend this product.
I installed the kit. It worked ok for the 2-3 times I used it. I believe on the third time I used it I noticed the running lights on one side were on in even though I didn't have then on. The brake lights and turning lights were not working. I managed to get through the short trip on that day and checked all the wiring. I hadn't made any mistakes installing the kit. Next time I hooked things up the fuse had blown. I took the vehicle to my cousin who has a business for pickup trucks. He took the taillights out and said one of the wires in the harness had pulled out. He said the wire was not secured in it's place when the harness was assembled. There was no way to see that when I installed the unit. I threw the unit away and my cousin installed another brand unit.
Fast FREE shipping, looks as though all components are included before installation.
What I like most is the VIDEO, recalling that a picture is worth a thousand words, and having worked at Kodak for 30 years, the video takes any guess work out of it.
Michael S.
1/26/2018
It worked GREAT, right up to the point when with my 5x10 utility trailer in tow, the 2015 Kia Sorento was totaled in a sudden snow squall, when a young on coming driver lost control and spun into my lane. The trailer held fast to that hitch.
The hitch and harness arrived 3 days before scheduled date and packed very well. Some minor rubbing on the tube, no big deal, I have paint. Dealer etrailer. Won’t install for another month, that review will follow then.
Alaska M.
7/30/2020
Great! All connections worked as advertised! Simple and straight forward.
Package contained everything promised in first class quality and instructions. Fit at all points was perfect and easy to install. Supplied instructions were clear and specific. I have experienced no adverse issues with the installed wiring. Highly recommend this wiring kit. My installation was on a 2016 Kia Sorento SUV.
Milt F.
3/21/2019
After one year the unit is still functioning perfectly. Quality product all the way.
Great Plug and Play wiring harness. Really happy with the results.
Wiring harness has quit working less than a year after purchase, one trailer brake light is always on, neither of the turn signals or the other brake light is still working.
Jenny N.
2/7/2024
It sounds like the harness has shorted out. To do a bit of trouble shooting, start by using a circuit tester to check the functions at the 4 flat connector. Also check the ground wire remains as a good solid ground to bare metal. You can then next check the signal of the wires leading into the converter box and out of the converter box. If you have a signal entering in the box and not out the other side then the harness will need to be replaced. I have a FAQ below that can help with testing the harness.
Helpful Links
Well made, super easy, all necessary components included in package.
Simple to install only thing I didn't use that was sent was the butt connectors. Personally don't like that style . Small issue with preference is all. Looks like it was factory done and not after like other wireing harness that I have seen or used.
Roger B.
2/19/2019
Have had one issue with it in a year. My right rear marker light will stay on if I leave the in line fuse in when no trailer is connected. Simple enough fix I dont pull a trailer that much so I just pull the fuse when Im not using it. Not sure if its auto manufacturer issue or trailer wiring issue but eh not that hard to overcome
Rachael H.
2/20/2019
Extremely helpful video on etrailer website convenienced me to purchase this wiring harness for my 2018 Kia Sorento. Every bit as easy as pie! A well engineered harness with plenty of length on the wiring and all the plugs matched. You may need additional black zip ties on hand if you’re picky like me.
Jim H.
4/28/2019
Installed it a year ago. Everything still works perfectly! Be sure to watch the video before you begin installation and you will be just fine!
Nicole T was a great saver of Get to g my vehicle ready to pull my trailer. The wiring harness I purchased thru a different supplier failed to ask a crucial vehicle option. It caused the wrong wiring harness to be purchased. I contacted Curt directly and Nicole T was on the job with her "A" game. She asked the right questions, allowing me to select the correct wiring harness. She arranged shipping to ensure I receive it as early as possible, the next day. Installation was quick & easy. Thank you Nicole T.
Pat A.
8/22/2019
Great, it has lived up to my expectations. Again, without Nicole T knowledge of your products & ability to ask the required information, I would have had to postpone my trip & spend additional money. Thank you again Nicole T & Curt.
The second install - a "Upgraded" system worked great. It was a plug 'n play so I didn't have to splice, solder and tape wires. Your video and printed instructions were very clear and spot on. Screwed the flat 4-pole mounting bracket to the hitch frame and used JB Weld to bond the flat connector to the mounting bracket.
thanx,
bill
Bill A.
8/16/2018
trouble free, no problems
Easy to install, I like how it isolates the electrical system and it works great. Your video instructions were outstanding. With the video a five year old could install the wiring. This was installed in my 2019 Kia Sorento. The first pix shows in the back very low profile, the second pix shows inside the engine compartment, truly cool.
Mr M.
3/5/2021
Ive had no issues at all. Works great. I did bottom-out once but it was my fault, deep ravine. The hitch seems to stabilize my rear end somewhat. Dont know if its good or bad. Forgot to mention, your wiring harness is super cool and easy to install.
Fit well and solid construction. Good v alue
Reed
12/22/2025
Great
Joanne was knowledgeable and helpful,with a great attitude and personality.Installing the kit was very easy one thing I added was a toggle switch in the power line to turn power off when trailer lights aren’t being used,I’m really satisfied with the kit
Easy plug n play
Best price quick delivery good item description only buying from etrailer from now on.
Super high-quality product at a competitive price. But etrailer’s fast service and detailed harness selection shopping tool are what drove my decision to buy here!
The trailer receiver was an easy installation, installing the wiring kit in a Kia Sorento was a pain.
We have been using the package for one year with no problems. Yes, I would order from Etrailer again.
My order was shipped promptly and arrived in good condition it was excactly as described.
This is the second trailer wiring harness that I have installed on a Kia Sorento. The first was on my 2012 Sorento. This one is on my 2014 Sorento. Having used the online video installation instructions the first time around and having no problems, I went straight to the video for my 2014 Sorento. The Curt T-Connector kit makes wiring easy. No splicing, just plug in the matching connectors, mount the power converter and run a few wires for a ground and forward to your battery. Hiding the wires behind the hitch as per the instructions with cable ties gives a clean look. I also mounted a Curt plug receptacle to the hitch so that the connector is not just hanging on the safety chain holes. As you can see from the photo I believe this gives a clean , professional look.
Looked up installation for my vehicle on YouTube.Piece of cake. Works great.
Ronnie E.
4/16/2026
I havent had any problems?
Claire H.
4/16/2026
This is such an easy wiring kit! Easy install...I was very impressed with how easy it was to install. Thank you!
Suspected my problem with the left signal and brake light was the harness. It was my harness I purchased 3 years ago. Hooked it up and all is well now.
Info for this part was:
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Charles
11/5/2024
Worked out perfect. I traded the vehicle and it helped with the trade in value.