To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.
Wiring a trailer doesn’t have to mean hacking into factory wires. This Curt T-Connector plugs right into the vehicle’s existing wiring for a clean, straightforward setup. There’s no splicing, guessing, or risk of mixing up connections—just a direct plug-in that’s ready to go.
Built with a powered converter, the harness pulls power directly from the battery instead of the tail light circuit. That keeps the trailer lights bright and consistent while protecting the vehicle’s sensitive electronics from overload or feedback.
The 4-flat connector gives you running lights, turn signals, and brake lights—all the basics you need for most small or mid-size trailers. Once it’s installed, it’s simple to plug in and hit the road with confidence.
The wiring tucks neatly away and routes through existing openings for a factory-style finish. Nothing dangles or looks out of place, so the setup stays protected from the elements and ready whenever you need to tow.
This harness is made for vehicles that didn’t come with a tow package. It gives you the same reliable trailer lighting connection as a factory setup without needing any dealer-installed options.

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Today we're going to be taking a look at the Curt T-Connector Vehicle Wiring Harness with the 4-pole Flat Trailer Connector. This product fits certain years and models of the Mazda 6. It's going to provide a 4-way flat connector at the back of the vehicle to power your trailer's signal lights. This is compatible with 5-pole, 6-pole, and 7-pole adapters. Adapters are sold separately. It's going to come with a dust cap for the 4-way flat plug. That way you can cover up the connection points when the plug is not being used. The black box is going to be be the included tail light converter. This is going to ensure that your vehicle's wiring matches that of your trailer's.
This is going to connect directly to the battery through the wiring to avoid overloading the vehicle's electrical system. The unit is constructed using surface-mount technology which is going to offer consistent, reliable performance. What that does is it maximizes the trailer light yield and intensity while producing minimal heat, and it ensures superior operation even in rough road conditions. While the benefits of a system like this is not only does it provide the 4-way flat connector at the back of the vehicle, but the installation is quick and easy. All you have to do is locate the connection points in the rear cargo area, and then you have these connectors right here that you'll need to plug in. They're going to snap-lock together for a nice, tight, secure fit. It does come with detailed installation instructions to indicate exactly where those connection points are, but the plugs are going to match up perfectly with one another. Get those plugged in then you'll need to make a ground connection, that's going to be the white wire with the ring terminal attached to it, you want to get that grounded on a nice clean metal surface, using the included grounding screw. Then you'll need to mount the converter box with the double-sided adhesive tape: peel that off, stick it to the back, and then mount the box to a nice clean surface. Next you'll need to run the hot lead to the vehicle battery.
Hot lead's going to be the short black wire coming out of the tail light converter box. This is going to get connected to the bundle of black wire with one of the included butt connectors. The other end of the black wire runs to the vehicle battery, gets another butt connector attached to it, and attaches to one half of the fuse holder. The other half of the fuse holder gets a ring terminal attached to it, and that connects to the positive post on the vehicle battery. It does come with a 10 amp fuse, and it's got the cap for the fuse box to keep the fuse safe and protected. Once that's done, you can secure any excess or slack in the wiring that you may have with the included zip-ties. Once your installation is complete, the 4-way connector is going to be stowed in an out of the way location within the cargo area. I also want to recommend that you use a small amount of grease on all your electrical connections, some dielectric grease. It is sold separately, but you can find it here at etrailer.com and that grease is going to help prevent corrosion to the connection points. When it comes to the maximum amperage for the stop and turn lights, we're looking at 3 amps per circuit and for the tail lights, we're looking at 6 amps per circuit. That's going to do it for today's look at the Curt T-connector Vehicle Wiring Harness with the 4-pole Flat Trailer Connector..
Ratings & Reviews
It work, fit fine, not hard instal
Great customer service! It doesn't get any better than this. Thank you!
Plug and play into the factory connections, except for the power lead. Went together quite smoothly.
Bought this for a 2016 Mazda 6i GT. Install was very straight forward and took about an hour (because I spent extra time to make sure the power wire was totally hidden). I was surprised to see that the battery even had an available connection for the additional accessory. Highly recommend this kit - worked first time I connected the trailer.
I loved how easy this was to install with no experience at all. Only took me 90 minutes and includes the wiring installation.
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.






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.