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Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Item # C86CR
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Custom Fit Vehicle Wiring

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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. Call 800-298-1624 to order Curt custom fit vehicle wiring part number C86CR or order online at etrailer.com. Free expert support on all Curt products. Guaranteed Lowest Price and Fastest Shipping for Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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  • Reviews (4)
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  • Videos (1)
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Curt Custom Fit Vehicle Wiring - C86CR

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • Converter
  • Curt

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.


  • Provides a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Connects quickly and easily
    • Locate connection points inside trunk, behind tail light housings
    • Plug in T-connector
    • Run hot lead to car battery
  • Includes a tail light converter to ensure that your vehicle's wiring matches that of your trailer
    • Powered module connects directly to battery to avoid overloading vehicle's electrical system
  • Constructed using surface-mount technology (SMT) for consistent, reliable performance
    • Maximizes trailer light yield and intensity while producing minimal heat
    • Ensures superior operation in rough road conditions
  • Comes with dust cap for 4-way flat connector


  • Maximum amperage:
    • Stop/turn lights: 5 amps per circuit
    • Tail lights: 7.5 amps per circuit
  • Limited 1-year warranty


This custom-fit T-connector plugs into your vehicle's wiring harness, which is located in your trunk behind the tail light housings. You will have to remove the trunk floor coverings and the rear and side scuff panels to access this harness. 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.

Powered Tail Light Converter with Surface-Mount Technology

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.

Curt SMT Circuit Boards

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.

56450 Curt T-Connector Vehicle Wiring Harness with 4 Pole Trailer Connector

Installation Details C86CR Installation instructions

This Product Fits The Following Vehicles

Video of Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Review of Curt Custom Fit Vehicle Wiring - Trailer Hitch Wiring - C86CR

Hey everybody. I'm Ellen here at etrailer.com. And we're going to take a quick look at the Curt T-Connector Vehicle Wiring Harness. This gives you a 4-pole flat trailer connector at the back of your vehicle, so you can transfer all of those lighting functions, your turn lights, your stoplights, and your running lights into your trailer, or any other accessory that uses that 4-pole flat.So let's take a closer look at what comes in the kit and talk a little bit about how it's going to be installed. The nicest thing about this kit is that you don't have to worry about cutting or splicing into your vehicle's wiring. It's just going to plug right in line between the tail light housing and that wiring from your vehicle, so really easy to put this in place.

You're not making any changes to the vehicle wiring. And if you ever decide to, you can always take this out, and you're not going to have changed anything about your vehicle at all. It also doesn't impede our day-to-day use of our vehicles' lights. Everything's going to function normally. We'll just be able to have that 4-pole at the back.This is a custom fit for the 2020 through the current Mazda CX-30.

This is kind of the brains of the operation right here. This is our module box, and this is going to protect our wiring from any kind of issues from our trailer and vice versa. It sends out the signals to that 4-pole to make sure that we have all our lighting functions, and it is filled with a potting material to help isolate that and make sure that nothing's going to go awry inside there. There's no water or debris that can get inside and cause any issues. And also, it's going to make it resistant to any kind of damage from impact or vibration while you're on the road.So once you have your connections to the back of your tail lights, the red, brown, and yellow wires will go on your driver's side, green wires go on the passenger side.

You'll have your ground connection to make with the white wire and then your power connection to make with the black wire. We'll get a length of bulk wire to run that up to the battery or our power source, maybe that's a fuse box for your vehicle. You want to put the fuse holder in between to make sure that there's no issues there, so it is going to be fuse protected. Comes with a 15 amp fuse to get that installed and also the butt connectors to make those connections and a ring terminal to actually go onto the positive side of the battery. Also get a few zip ties and a dust cover for our 4-pole to make sure that that's protected from any kind of water and other things getting in there.

There's also a piece of nice foam tape to put on the back of the box to make sure that that's mounted up in a good spot and a self-tapping screw to make your connection for the ground wire. Also comes with the complete instructions on how to get everything installed, so you don't have to just remember from what I have to tell you.As far as the specs, the max amperage for our stop and turn lights is going to be 5 amps per circuit for the tail lights. It's 7.5 amps per circuit.That's pretty much all there is to it for our look at the Curt T-connector Vehicle Wiring Harness. Whenever you do have that completely installed, a lot of times, you can just run that 4-pole out of the back hatch of your vehicle. That's the easiest way to do it. Some people don't like the look of that, and so if you want to, you can go for a more permanent looking mount. That would require getting a couple of brackets to mount that 4-pole nearer to the hitch. You can find those and all kinds of other accessories here at etrailer.com to complete that install, so check them out.Thanks for watching.

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C86CR

Average Customer Rating:  5.0 out of 5 stars   (4 Customer Reviews)

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.

- C86CR

I'm from Canada and looked many places for this item. Sources in Canada did not have inventory, and it is hard to find a US based vendor willing to ship to Canada. The representative at etrailer was great. The process to find and purchase this item was easy, it was offered at a fantastic price and even with exchange, duty, and shipping, it cost less than the same item offered anywhere else - Canada/US. Shipping was quick with detailed tracking. Was a real pleasure doing business with this vendor. Highly recommend.

- C86CR

- C86CR

- C86CR
2021 Mazda CX-30


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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Kathleen M
Installed by:
Kathleen M
Employee Kristina F
Written by:
Kristina F

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