To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.
Wiring a trailer can be a hassle if you have to splice into factory wires. This Curt T-Connector makes it easy with a plug-in design that connects directly to your vehicle’s existing plugs. There’s no cutting or guesswork—just click the connectors together, route the 4-flat harness, and you’re ready to tow.
The powered converter sits out of sight and protects your vehicle’s sensitive electronics while powering your trailer lights. It draws power directly from the battery instead of your tail light circuits, which keeps the system safe from overload or signal errors. You get full lighting function without visible wiring clutter or interference with your factory setup.
The 4-flat trailer plug gives you everything you need for basic towing—running lights, turn signals, and brake lights. It’s the standard connection used on most smaller trailers, so you can hook up and go without any adapters or extra wiring.

Not every vehicle comes ready to tow, but this harness fills that gap. It’s built for models without a factory tow package, giving you a reliable vehicle-end connector that performs like OEM wiring. You get dependable trailer lighting, even if your vehicle wasn’t originally equipped for it.
This will not affect how the tail lights on your vehicle operate.
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hi there, I'm Michael with etrailer.com. Today, we're gonna take a quick look at this Curt T-connector vehicle wiring harness. This wiring harness is going to be a custom fit for your 2021 and newer Hyundai Sonata. This is going to make it very simple to have a four-way flat trailer connector on the back of your Sonata so that you can hook up to a trailer and be legal and allow your vehicle's tail lights to power your trailer's tail lights so that other motorists, as they're coming up behind you, they can see if you're driving at night, if you're turning, braking, that sort of thing. So this is gonna be very important for you. This four-pole connector can work with four-pole connectors on your trailer.
If you have a five-pole or a six-pole or a seven-pole, we do have adapters available here at etrailer.com that will allow this four-pole to adapt to your trailer's wiring so that everything will still work for you. Now, the main benefit of a system like this is that it's gonna be so simple to install. Really, anybody can do it. You don't have to be a mechanic. They do include instructions here for you, to walk you through step by step how to get access to your tail lights.
And once you have access, you're basically just going to unplug your vehicle's tail lights from the wiring and then plug in this cable to the wiring, and then to your tail lights, that will reconnect that circuit, so your taillights on your vehicle will function like normal, even when you're not towing. But then when you are towing, it's going to send that signal out to your trailer. So you'll get this hooked up on your driver's side, run this over to your passenger side. Your white wire here is a ground. So they include a self-tapping screw for you to get that ground to a metal surface.
And then your black wire is gonna be a power wire. So they do connect to your vehicle's battery to give a little bit of extra power to the system so that it's not putting too big a strain on your vehicle light wiring. So will run up to your vehicle's battery. They do include some additional wiring here to make that connection. Once you get up to your battery compartment, they do include a fuse holder and a fuse that you'll get wired in place and then connect to your battery.
And so really, that's the hardest part of this whole process, is getting that wired in place. But the plug and play-style back at your tail lights is gonna make it very simple to get installed rather than having to cut into your vehicle's wiring, potentially void your vehicle's warranty. This system is gonna be much easier, more foolproof, and allows you to get everything connected in place. So very simple process to get installed. And then it is going to use that battery power to power up the unit. So this will provide six amps per circuit for your stop and turn lights. It's also going to provide three amps per circuit for your tail lights. This is a nice construction and it's got this potting material in here to prevent any disconnect. So as you're going down the road, even if you're in a really bumpy area, this potting material is gonna hold those connections to the circuit board so that you're not gonna have to worry about them coming loose. So very, very nice set up here for you to get your vehicle set up to tow a trailer, make sure that your lights are gonna be operational on the trailer. So that's gonna complete our look for today. I hope this video has been helpful for you in determining if this is the right wiring harness for you. This is a custom fit, so you might be limited to your other options. So if you are looking for a wiring harness, this is gonna be a great option for you. That's gonna complete our look for today. Thanks for watching..
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