Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
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2009 GMC Acadia
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2009 GMC Acadia
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Hooking up trailer lights doesn’t need to be complicated. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector plugs directly into your vehicle’s factory wiring behind the tail lights. There’s no wire cutting or splicing required—just plug in the connectors and you’re ready to go.
Heavy trailer loads can overload factory circuits, but this harness includes a powered ModuLite converter that solves that problem. It draws power straight from your vehicle’s battery instead of the tail light wiring, so your electrical system stays isolated and protected. That means steady, reliable lighting for both your vehicle and trailer.
Whether your trailer has LED lights or traditional bulbs, this harness keeps everything working together. The converter ensures the correct signal output for each light type so your running lights, turn signals, and brake lights stay bright and in sync every time you tow.
The harness installs behind the interior trim panels near the tail lights for a clean, factory-style finish. The 4-flat trailer connector routes neatly out of sight when not in use, keeping everything tucked away and protected from dirt and weather.
Once installed, you get a standard 4-flat connector ready for basic trailer lighting—running lights, turn signals, and brake lights. It’s the dependable setup most small trailers use and makes connecting to a trailer quick and straightforward every time.
Customer Satisfaction Score:
94% were satisfied with this product
6% of customers were not satisfied
Ratings & Reviews
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.
Installation was very straightforward, the instructions are fantastic.
I did find that mechanics wire was more useful than the included wire for the part where you have to fish wires behind the bumper. Other than that it was as expected with anything you buy from etrailer.com, GREAT!
The wiring harness doesn’t connect correctly. The blinkers will not work after long hours of effort.
Geneva
7/18/2024
Still unable to get the blinkers to work with the wiring harness.
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.
Ordered the Hitch and wiring kit separately but the ETA for both of them was spot on the install was fast, even faster with bumper removed (three screws four bolts) hauls my 4x10 trailer with a hobie pro angler 14 below and a vibe maverick supb and fishing rod box on the ladder rack above with no problem
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.
Good quality, great service as always from etrailer. A little more complicated on some Kia models due to needing the power run from the battery, but we had a professional vehicle accessory place so that wire after we did the rest of the effortless initial install, and everything came together just fine.
IT SHIPPED FAST INSTALLATION WAS EASY AND IT WORKS GREAT
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.
Michael
7/20/2021
Still no issues. Wiring harness continues to function properly.
This harness worked perfectly for the 2020 Hyundai Tuscon! The instructions provided by etrailer.com 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!
Paul
10/27/2023
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.
Mike L.
11/13/2023
The Hitch and wiring harness fit perfectly! I used a tool box and some blocks of wood on the right side under the 2021 Kia Soul to hold up the hitch once I got it in place then started bolts on left side, then placed bolts in right side. Light harness took more time due to had to remove panel on left side under car to route wire thru same area that the brake line are routed. The hardest thing was mounting the little black box on left side under car, found a hole already in car where I took a small bolt and nut to secure the black wiring harness box. Biggest thing is just preparing everything and just take your time, I wasn’t in a hurry and took my time plus some breaks which the whole hookup took me 2hours. If you don’t block up the right side of hitch I do recommend lowering the muffler so you don’t damage it.
Fit was perfect and the wiring harness worked as advertised. Price was good and delivery was very fast. I have used the hitch to pull my tilt bed trailer many times to move things and take kayaks to the lake for family outings. Perfect for my needs.
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.
Katrina B.
3/28/2023
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.
Abbey was very helpful in this purchase. Very professional and considerate.
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 etrailer.com! Perfect company (as usual)!!! Thanks for the quick shipping!
Brent
7/6/2021
Great product. No issues at all and is still working perfect.
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.
Jenny N.
10/30/2023
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.
Helpful Links
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!
Mike
11/12/2023
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!
Mike L.
11/17/2023
Helpful Links
Item doesn't fit
This was easy to install and continues to work flawlessly 1 year later. I purchased this for my Kia soul so I can tow my utility trailer with two motorcycles on it and it has worked out perfectly.
seams to fit okay. instructions could be better.
Jess
7/23/2025
could not be better. no problems at all. would recommend to anyone.
Using the installation video was of great help. Easier than I thought.
The only problem I had is, I did not know. I had to run a hot wire from the battery all the way to the back of the car, but it was not that difficult.
A exact match to my vehicle with installation videos of my exact vehicle. Lot's of places carry the same product but not the same service.
Awesome thanks
This harness was installed on a 21 Kia Seltos. Installation went smoothly thanks to the videos provided by Etrailer. The installation was done in about 45 minutes and would have been quicker if I had been more firm with the taillight assembly removal. No interference or changes noticed with the original vehicle lighting.
I appreciate the plug and play kits, but the harness that goes to the left-hand taillight needs to be longer on this one. The tag specifically states the module must be placed inside, but the only ways to reach the taillight well on a Seltos are through the original harness grommet which the connectors prevent, or out the floor plug and back up the outside, but the harness won't reach.
Bla
5/22/2026
I had to cut and reconnect the wires going to the lights since the connectors dont fit through the grommets, and routing them on the outside could interfere with the radar modules behind the rear fascia, but after I completed the installation its been working perfectly. I hope they redesign this by using an actual vehicle.
Kate F.
5/22/2026
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Jenny N.
7/17/2024
Geneva, I can help troubleshoot with the harness. Has the harness just started this or has it always done so? I will first recommend checking the ground connection on the vehicle. Make sure it is a good ground to bare metal. If the ground is good, I would then use a circuit tester like # PTW2993 to test the right and left hand light location on the 4 way. If the signal is not reaching the 4 way then testing the wires before the converter box and after the converter box to see if the signal is making it through. If not then the harness would be considered defective. I also have a FAQ below that will help.
Helpful Links
faq-4-5-way-troubleshooting.aspx