To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.
Wiring a trailer often means dealing with factory wires, but this Curt T-Connector skips all that. It plugs straight into existing connectors to give you a 4-pole flat trailer plug. No cutting, no tracing wires—just a clean plug-in that’s ready to go.
This harness uses a powered converter to isolate and protect your vehicle’s sensitive wiring from potential overload or feedback from the trailer lights. It makes sure everything runs safely and reliably every time you tow.
The included 4-flat connector covers the basics—running lights, brake lights, and turn signals—so your trailer stays fully visible and street legal. It’s the standard connection used on most small and midsize trailers.
Designed to stay out of sight, the harness tucks neatly behind panels or trim for a factory-style finish. The hidden setup keeps your wiring protected and gives the back of your vehicle a clean look when you’re not towing.
If your vehicle didn’t come with wiring from the factory, this kit fills that gap. It supplies everything needed to add trailer lighting without having to buy or modify extra components. Plug it in and you’re ready to tow safely.

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hi, everybody, Andy here with etrailer.com. Let's take a real quick look at this CURT T-connector vehicle wiring harness with four-pole flat trailer connector. Now, this harness has been designed to fit your 2023 and newer Toyota Crown. And on custom-fit parts such as this harness, I do recommend taking advantage of our vehicle fit guide here at etrailer.com. Simply input the year, make, and model of your vehicle, and our fit guide will confirm if this will work for you or if we have something comparable that will work for you. So this is going to give you a four-way flat trailer connector at the back of your Crown to power your trailer's signal lights.
This will also be compatible with five-, six-, and seven-pole adapters. Those adapters are sold separately. As you can see, this does come with a dust cap for that four-way flat connector when it's not in use to protect those connection points. And as you know, a well-lit trailer is a safe trailer, so this four-way wiring harness is gonna keep your trailer's brake lights, turn signals, and running lights powered and sync, and in sync, rather, with your Crown. So whether you're hauling a boat to the lake or a camper to the mountains, your lights are gonna stay bright and visible.
Now, these custom-fit T-connectors are going to snap directly into your factory wiring harness. So you'll get your trailer lights up and running without any cutting or splicing. You're just gonna plug these in and you're gonna be ready to tow. The vehicle's wiring harness is often behind a trim panel or under the cargo floor. Some vehicles may require removing interior panels or lifting carpeted sections to reach it.
But once accessed, this harness installs easily with these T-connectors. Now, some vehicles can't handle the extra electrical load of trailer lights. The built-in powered converter here is gonna draw power directly from your Crown's battery, ensuring a steady, protected current to your trailer while keeping your vehicle's circuits from overloading. So this kit does come with everything that you are going to need. As you can see, it does come with a fuse holder.
And then within this hardware bag is gonna be a fuse, butt connectors, cable ties, and adhesive strip here for mounting the converter box. You're gonna get a tube of black silicone, and of course, instructions to guide you through that installation process. So really, you shouldn't need any extra parts installing this kit. You should have everything that you need. Now, it is also recommended that you use a small amount of dielectric grease on all of your electrical connections, like the plugs on the vehicle and the four-pole flat connector itself. That grease is designed to help prevent electrical failures caused by corrosion and moisture. So on your screen, I am including the part number for that grease. You can take that part number, pop it in the search field of our website. That will take you to that grease and you can add that to your order if you so desire. Once you get this installed, we would love to hear back from you regarding your experience with getting this installed and even using it. And you can share your experience with us by dropping a comment or leaving a review on this product page. Let us know how it's working out for you. We would love to hear back from you. Well, that's gonna wrap up our look today. I do hope that our time together has been helpful for you. Again, my name is Andy. Thank you for joining me.
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