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Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring. Powered converter reduces strain on wiring system and is made using SMT to ensure superior performance.
Features:
Specs:
Installation
This custom-fit T-connector plugs into your vehicle's wiring harness, which is located behind the driver's-side and passenger's-side tail lights. To locate this harness, you will have remove the storage tray cover and floor access panel. Once you've plugged in the T-connector, run the hot lead up to your car battery. Connect the lead to the included fuse holder, and then connect the fuse holder to the positive terminal on your battery.
Once installation is complete, the 4-way connector will be stowed in an out-of-the-way location within your trunk.
It is recommended that you use a small amount of grease on all electrical connections - the plugs on your automobile and the 4-pole connector itself - to help prevent corrosion.
A tail light converter is built into this T-connector. This converter is a circuit-protected, battery-powered unit that bypasses the electrical routes that are used by a basic wiring harness. As a result, there is virtually no draw on your tail light circuits.
Because most trailers run on a two-wire system - wherein the brake and turn signals are carried on one wire - the separate brake and turn signals from your vehicle's three-wire system need to be combined so they are compatible with the wiring system of the trailer. This converter combines the brake and turn signal functions of your automobile so that they run on one wire to properly activate your trailer's tail lights. Note: This will not affect how the tail lights on your vehicle operate.
Curt builds each tail light converter using surface-mount technology (SMT). This method of construction involves soldering electronic components directly to the surface of a printed circuit board. SMT eliminates the need for leads, which are used in older through-hole technology. The result is a circuit board that is smaller yet provides more routing area and that offers superior performance, reliability and durability.
Circuit boards constructed using SMT have been shown to perform better under rough conditions with excessive vibration than those made using the through-hole method. And where would vibration be more likely to occur than in towing applications? Curt converters also produce less heat, leading to increased durability and longer life. In addition, lower levels of resistance ensure better performance, especially for parts that operate at higher frequencies.
Each Curt circuit board is made using high-quality components that are pieced together in the most technologically savvy fashion, leading to greater predictability and reliability in functioning.
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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 look together at this Curt T-Connector Vehicle Wiring Harness with a 4-pole flat trailer connector. Now, this wiring harness is custom designed to fit your 2023 and newer Kia Niro and Niro EVs. And so, on custom fit parts such as this wiring 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. Now, this harness is going to give you a 4-pole flat trailer connector at the back of your Kia Niro to power the trailer signal lights.
This is compatible with 5-pole, 6-pole, and 7-pole adapters, and of course, those adapters are sold separately. And as you can see here, included with this is a dust cap for that 4-pole flat connector. So that dust cap is going to cover up those connection points just like that when this plug is not being used, so those contact points are gonna be clean, free from dust and debris when you are using that cover. Now, the black box here at the back of our wiring harness is a powered taillight converter. This is going to ensure that your vehicle's wiring matches that of your trailer.
This connects directly to your vehicle's battery to avoid overloading the vehicle's electrical system, reducing strain on your vehicle's wiring system. Curt, by the way, builds each converter using surface mount technology for consistent, reliable performance. This maximizes trailer light yield and intensity while producing minimal heat, ensuring superior operation in rough road conditions. Now, this harness is designed to connect quickly and easily. You will need to locate your vehicle's wiring harness behind the driver's side and passenger's side taillights.
You will have to remove the storage tray cover and the floor access panel. And once you locate those connectors, then you're gonna separate the connectors. And you wanna be careful not to break the locking tabs, and then you're going to insert the T-connector ends between the vehicle's wiring connectors and lock them into place. These T-connectors are fitted for your Kia Niro and Niro EV. So they are going to match up perfectly with those connection points on your vehicle, they're just going to snap and lock together for a tight, secure fit.
Now, once you have these connectors plugged in, you will need to make a good ground connection. The ground wire is this white wire, and it has a ring terminal attached to it. And so, this does come with a self-tapping screw as you can see there, so you can get this grounded to a suitable location, such as your vehicle's frame or crossmember. You just wanna make sure that the surface is clean and rust free. Next, you will wanna mount your converter box to a safe, out-of-the-way location. You can do that with maybe another mounting screw that you might have on hand already or with this included double-sided tape that I have right here. Or you can use one of the many cable ties that's included with this kit to secure this converter. Next, you will need to run this hot lead wire to your vehicle's battery. So that's this short black wire here that's coming out of our converter box. This short black wire is going to get connected to one end of this included bundle of black wire using one of the included butt connectors that you see there. And then the other end of this bundle is going to get routed to your vehicle's battery. So once you have this routed to the battery, you're going to take this fuse holder that you see right here, and then you are going to, with the second butt connector, connect the fuse holder to the routed wire that you ran to your battery. And then, you will take the other wire here from this fuse holder and connect this included terminal. And that is going to then, the ring terminal is going to get attached to the positive post of your vehicle's battery. This does come with a 10 amp fuse, and so, after you have this all connected, you'll pop that fuse into place, and then this fuse holder has a cap to keep that fuse safe and protected. Now, you can secure any slack that you have in your wiring with the many cable ties that's included in this kit. And then once installation is complete, the 4-way connector can be stowed in an out-of-the-way location within your trunk, or if you choose, you can mount this at your trailer receiver hitch with one of the bracket options that we have available here at etrailer.com. So the maximum amperage for the stop/turn lights is three amps per circuit, and the taillights, a six amps per circuit. Instructions are gonna be included to guide you through that installation process. It is also recommended that you use a small amount of dielectric grease on all of your electrical components, like the plugs on the vehicle and the 4-pole connector itself. The grease is designed to help prevent electrical failures caused by corrosion and moisture. So if you wanna check that grease out on your screen, I am including our item number. You can just take that item number and put it in the search field of our website. That will take you to that dielectric grease, and you can add that to your order if you so desire. Well, that's gonna wrap up our brief look today. I do hope that it was helpful for you. Again, my name is Andy. Thank you for joining me.
The connector worked fine. The wires for the directionals were barely long enough to reach the directionals, a few extra inches would have been appreciated. The wire leading to the 4-pin connector is very short and I will need an extension if I want it to stick out of the tail gate.
Install on a Niro EV went OK except for connecting the brake & running light connector. The suggested plug was an air valve on our car. I used the connector in the center back just above the hitch. Also I ran the power wire through the car above the doors and out the same hole as I didn't want the wire laying on top or under the battery unit.
Testing it the lights all seemed to work using a tester plug OK but has not been verified on a trailer yet.
The written instructions don't pertaining to the 2025 kia niro EV although the website says the kit does. Customer service verified this. I unnrcessarily removed the hitch to route wires only to find out later the instructions hadnt been updated. Lost several hours doing this uneccesary work As others stated the wires should be longer for easier fit and so that the control unit can be mounted further from the exhaust area. Website video also conflicts with written instructions. Routing the power wire to the battery was also very difficult.
I won't know until I install it, this s pring.
The taillight connectors work but don't "click" together. Be prepared to cut and extend the wires because the turn signal wires are too short- the signal wires and 4 wire connector each need to be about a foot longer. The sealant the instructions say is included isn't.
The assistance ikn getting the right item was much appreciated. Alos, good, speedy delivery.
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Chris
9/5/2025
Still working perfectly.