To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.
Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.
Error submitting comment. Please try again momentarily.
This harness skips the messy part of wiring and plugs straight into the factory connectors behind the tail lights. There’s no need to splice or modify any existing wiring. It’s a direct plug-in setup that keeps everything neat and hidden out of sight once installed.
LED setups can be tricky since they draw less current, but this harness includes a powered converter that connects directly to the battery. That separate power feed protects sensitive electronics while making sure your trailer lights work properly every time.
Once installed, the 4-flat connector gives you all the basic functions—running lights, turn signals, and brake lights—so your trailer stays visible and road legal. It’s ready to pair with most small trailers and can also connect to a 7-way kit if you decide to add one later.
Each wire in the harness is built with 14-gauge conductors for solid current flow and long service life. That heavier wire helps prevent voltage drop, supports consistent lighting performance, and stands up well to vibration or exposure behind body panels.
Customer Satisfaction Score:
89% were satisfied with this product
11% of customers were not satisfied
Ratings & Reviews
Bruce
4/11/2026
Item still functioning as it should, my trailer lights work well.
Jenny N.
2/25/2023
Yep, it really depends on the vehicles wiring as to how simple the installation will be. I appreciate a good shortcut however I need to say that actually running the power wire to the battery is the best bet. Wiring it to anywhere else may damage the vehicle wiring as it could overload it. I have a helpful FAQ for tips on running the wire to the battery.
Helpful Links
Thomas M.
1/24/2022
I have reached out to Curt, they mentioned that this harness will only work with LED tail lights. They have passed this issue to their engineering team to research.
Jenny N.
9/20/2022
I recommend watching the video review that we have in the link below.
Jenny N.
4/6/2022
When the fitguide is used for a 2021 Ford Bronco and the wiring harness option is ed there is a down menu to choose whether the Bronco has LED tail lights. For those without LED tail lights you would want to use part # 119190KIT.
Mike L.
8/26/2022
It could be possible you purchased the wrong harnesss. The Curt # C42WR you purchased is for 2022 Ford Bronco models with LED taillights. If you do NOT have LED taillights, youd need part # C87BR instead.
Do you have a question about this Custom Fit Vehicle Wiring?
Info for this part was:
At etrailer we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.
Robin H.
10/7/2026
I would still check the ground. It needs to be secure on a clean, bare-metal surface. This is pretty typical behavior for a bad or loose ground connection. If it still isn't working properly, check for power running into and out of the converter box to make sure it is working properly.