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Wiring a trailer harness doesn’t have to mean cutting into your vehicle’s wiring. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector plugs right into factory connectors, so everything stays neat and reliable. It’s a true plug-and-lead design made for an easy DIY setup with no splicing required.
The integrated converter keeps the vehicle’s lighting signals working properly with the trailer lights. It balances the load between turn, brake, and running light circuits so your trailer lights operate cleanly every time you connect.
The 4-flat connector gives you all the essentials—running lights, turn signals, and brake lights. It’s the standard setup for small trailers, so once you plug in, your trailer lights will match your vehicle’s signals immediately.
The harness stays tucked away when not in use thanks to its hidden, vehicle-end connector design. You can route it cleanly through existing trim or grommets for a professional look that doesn’t leave wires hanging or exposed.
The harness includes clearly identified wire leads for each side. The yellow lead routes to the driver’s side and the green to the passenger’s side, so you always know which cable goes where during install. The shorter side is where the converter mounts for a solid fit and simple finish.
Ratings & Reviews
Leonard
10/7/2026
Its working perfectly after a year. I dont use it on a regular basis. Only when I take long trips. Its not used to hookup a trailer or anything of that sort. Its only used for an extra set of lights on the back of the car. To replace the third brake light which is hidden with my bag. I have a special rubber traveling bag fixed on the back of the trunk of the car. Its an MX5 Roadster, the trunks are small. I dont use it regularly. I would have been very surprised if I would have problems with it. Its never out in the elements at any time.
Jerry B.
10/8/2026
Gwendolyn Y.
7/25/2025
Can’t wait to hear how everything goes, what’s the arrival date for the trailer?
Bigote
8/13/2025
Super well. Pulls both my 2x5 box trailer and my 5x8 flat trailer with no issues.
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Lazer S.
3/24/2026
Glad to hear it's working well for you, Don! Well, mostly. Little odd that the left signal is causing all the lights to flash. First thing to check is your ground. Make sure it has a good clean connection and it isn't stacked with other ground sources (this is a common practice that I really don't like). If that's good, was the 5th port on the trailer for reverse lockout or something else?