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Wiring a trailer doesn’t have to mean tapping into factory wires. The Curt T-Connector with 4-pole flat trailer connector plugs inline with the vehicle’s existing tail light wiring. There’s no cutting or soldering — just plug in the connectors and it’s ready to go.
The harness provides a standard 4-flat connector that handles running lights, turn, and brake signals for most small and medium trailers. It’s the basic setup you need to safely tow utility trailers, campers, or boat trailers with working lights right out of the gate.
A built-in powered converter isolates the trailer wiring from the vehicle’s sensitive electronics. If there’s a short on the trailer, it protects the vehicle’s circuits by absorbing the fault instead of passing it upstream. This keeps the factory system safe and prevents costly repairs.
If you ever move up to a larger trailer with electric brakes or onboard charging, this 4-way harness can be expanded using a 7-way installation kit such as the ETBC7. It connects right to this harness so you can add brake control wiring and a 12-volt power feed without redoing your entire setup.
Each wire in the 4-flat connector corresponds directly to a light function — yellow and green for turn signals, brown for running lights, and white for ground. That makes testing and tracing any issue straightforward with a simple circuit tester, so you can diagnose and fix problems quickly.
Customer Satisfaction Score:
95% were satisfied with this product
5% of customers were not satisfied
Ratings & Reviews
Easy to install works great and still going strong.
Working well one year on in my Kia Sore nto.
Worked liked a charm. It's a year later and no problem.
It's been a year now and I couldn't be happier
Very easy to install, haven't had any trouble with it works great
Nice harness easy to install and the directions were accurate
This worked perfectly and was easy to install. One year later and it still works great.
This wiring was for our back-up tow vehicle, so we only recently used it. Worked great, and no issues!
Very pleased with the product, the service, and the technical advice available. Would definitely recommend to friends.
Great product easy Internet site
to view
excellent instructions. perfect fit.
Made well and simple installation.
This was the exact wiring harness I needed. Flawless performance so far and easy to install.
Super easy installation, got the wiring done in 20 minutes and everything works perfectly. The only complaint I have is that I paid for two day shipping and got it in three days. Don’t know whose fault this is but when a person pays for something expedited the expect to get what they pay for, otherwise could t be happier.
I have reordered the right harness. I received the wrong information from the car dealer I bought the vehicle from. Tyler was very helpful with my reorder. I don’t have the hitch on yet so no pics at this time.
Wiring harness installs rather easily. It would be better if the wires were longer going from the driver side tail light connection to the module to allow more room for attaching it to the chassis.
Works well. Some problems with the fuse adaptor that pulled out of its connector. I have to hot-wire it, but I can deal with that.
This wiring kit makes the job much easier. Like others though, I do wish Curt would a few inches of wire to the passenger side of the harness. All connections fit like factory.
It was so easy to find the correct trailer hitch / tow package I needed for my car! The order came very fast, and the staff were very quick to respond to my questions! I returned one item (my husband wanted to get a different one for his car), and thy were super helpful with the return as well as the new item!! Overall, it was a great and easy experience!!
Fairly easy to install. Just plugs in. Only complaint is the driver's side wiring harness is about 6" short in my opinion. The control box lays on top of bumper support because the harness wasn't long enough to allow control box to come down to be mounted like instructions said. The bumper support on the Kia is an open matrix structure, so there isn't anyplace to mount the box to on top. If the harness was 6" longer, it could have been solid mounted to the forward facing side of the bumper support.
Greg
6/12/2023
After a year, no issues. Harness still works fine. Not had any issues with lights working once plugged in.
Mike L.
7/12/2023
Good quality, manual showings step by step instructions,
Mach my vehicle 2012 Kia sorento LX 2.4 l,
If possible to add where to connect positive inside fuse box under the hood to instructions will help others
Evgeny
4/11/2025
1 year later still working as intended, survived Canadian winter.
Great job and thank you for your business!
Excellent quality, everything working perfectly.
Thank you so much!
I bought this trailer wiring harness about a year ago, and it’s been solid ever since. I’m fairly handy, but this was my first time installing one. I wasn't too difficult and it’s still working multiple uses, which is nice.
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Ralph
3/24/2022
works great