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  1. Custom Fit Vehicle Wiring
  2. CURT
  3. 4 Flat
  4. No Tow Package
  5. Trailer Hitch Wiring
  6. Vehicle End Connector
THIS ITEM IS NOT A FIT FOR
2020 GMC Sierra 3500
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CURT

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

Part Number: C37NR
In Stock
$95.87
Retail:$159.95
You Save: 40%
Custom Fit Vehicle Wiring
Not Confirmed to Fit

2020 GMC Sierra 3500

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etrailer Installation
We'll connect you with nearby partnered installers who know this exact setup.
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. 1-800-940-8924 to order CURT custom fit vehicle wiring part number C37NR or order online at etrailer.com. Free expert support on all CURT products. Great prices 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 (8)
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  • Videos (1)
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CURT Custom Fit Vehicle Wiring - C37NR

Highlights

  • Custom Fit for Your Vehicle: Works with your vehicle's wiring
  • Tow Without Factory Prep: 4-way connector powers trailer signal and running lights.
  • Plug-and-Play Install: T-connector plugs into existing ports—no cutting or splicing.
  • Clean, Factory-Style Fit: Uses vehicle’s trim paths for a hidden, professional wiring look.
  • Protects Vehicle Electronics: Powered converter isolates trailer load from vehicle circuits.
  • Versatile Trailer Use: Works with standard 4-flat accessories like light kits and adapters.

Features to know about

Installs Without Cutting or Splicing: Plug-In T-Connector

Wiring a trailer doesn’t have to mean cutting into factory wiring. This Curt T-Connector harness plugs straight into the vehicle’s existing connectors to create a 4-pole flat trailer plug. It’s fully plug-and-play, so the install stays clean and simple without any splicing or special tools.

Reliable Trailer Lighting: 4-Flat Connection with Powered Converter

This harness provides the essential lighting signals — running lights, brake lights, and turn signals — through a standard 4-flat connector. The built-in powered converter keeps the trailer wiring isolated from the vehicle’s sensitive electrical system, helping prevent overloads or signal issues with LED or Canbus setups.

Designed for Vehicles Without a Tow Package: Ready to Connect Out of the Box

For vehicles that didn’t come with factory trailer wiring, this harness fills the gap without requiring extra factory parts. Everything needed comes attached to the plug-in leads, so it’s ready to install right out of the box.

Clean, Factory-Style Setup: Plug and Lead Design

The plug and lead layout makes routing wires easy and tidy. The connectors fit in line with existing plugs, keeping everything tucked away and looking like it came from the factory. Once connected, you’ve got a dependable 4-way socket ready for towing lights whenever you need it.

Specs

Specs

Comparison chart showing Curt trailer wiring harness types with labeled connectors and callouts for features and specifications.

  • Image Description: This image appears to show a comparison chart for Curt trailer wiring harnesses, likely illustrating different connector types or wiring harness options.
  • Chart Details: It includes labeled segments or callouts, possibly identifying product variations, connector styles, or compatibility notes.
  • Purpose: This image is best suited for the product comparison or technical specifications section of the description, helping customers differentiate between similar Curt T-Connector wiring harness models.

56482 Curt T-Connector - Surface Mount Technology - 4 Wire

Similar to Tekonsha TK67VR

Installation Details C37NR Installation instructions

This Product Fits The Following Vehicles




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

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




Video Transcript for Let’s Check Out the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector-C37NR

Hi, everybody. Andy here with etrailer.com and today we're gonna take a look at this Curt T Connector Vehicle Wiring Harness with four pole flat trailer connector. Now, this is going to fit your 2020 and newer Mitsubishi Outlander Sport. To confirm that this is going to work for your vehicle, take advantage of our vehicle fit guide and input the year, make and model of your vehicle and our fit guide will let you know if this wiring harness will work for you or if we have something comparable that will work for you. Now, this harness is going to give you a four pole flat trailer connector at the back of your Outlander Sport to power your trailer signal lights. It is compatible with five poles, six pole and seven pole adapters, and of course those adapters are sold separately.

And included with this is this dust cap that's going to cover up those connection points when this is not in use. So, that's going to protect it from dirt and grime and moisture and then when you're ready to use it, just remove the dust cap and you'll be ready to roll. Now, the black box on this harness is a powered taillight converter and this is going to ensure that your vehicle's wiring matches that of your trailer. It connects directly to your vehicle's battery to avoid overloading the vehicle's electrical system, reducing strain on your vehicle's wiring system, and Curt builds each converter using surface mount technology for a consistent, reliable performance. It 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. The connections with the yellow wires that we have right here are gonna go to your driver's side and the connections with the green wires are going to go to your passenger side of your vehicle. You will need to locate your vehicle's taillight wiring harness behind the driver's side and passenger side taillights. And then you will have to remove the taillight assemblies to access this harness, and once you locate the vehicle's taillight wiring connections then you're just going to separate the taillight connections and you wanna be careful not to break the locking tabs and then insert these T connector ends between the vehicle wiring connectors and lock them into place. These T connectors are custom fitted for your Outlander Sport, so they're gonna match up perfectly with the connection points on the vehicle and they're gonna snap and lock together for a tight, secure fit.

Now, once you have these plugged in, you will have to make a good ground connection. And so, the ground wire is this white wire with this ring terminal attached to it and it does come with a self-tapping screw. So, you can get that grounded to a suitable location, such as your Outlander Sport's frame or crossmember, and you just wanna make sure that that surface is clean and rust free. Then you'll need to mount this converter box to a safe, out of the way location. You can do that with another mounting screw or with this included double-sided adhesive tape or even with one of the many cable ties that's provided in this kit.

Next, you will want to run the hot lead to the vehicle battery and that's this short, black wire that's coming out of the converter box. This short black wire gets connected to one end of this included bundle of black wire using one of the included butt connectors. And then, the other end of this bundle is going to get routed to your vehicle's battery. And once you have this routed to your battery, you're going to take this fuse holder and connect one of the wires with the second butt connector to the routed wire, and then, the other half of this fuse holder will get a ring terminal attached to it. And that's going to connect to the positive post of your vehicle's battery. This does come with a 10 amp fuse and that's gonna go right into the holder, as you can see. And then, this does have a cap to keep that fuse safe and protected. Now, you can secure any excess or slack in your wiring with the included cable ties and you're gonna get quite a few cable ties to secure all the wiring up. And once the insulation is complete, the four-way connector will be stowed beneath your vehicle near the trailer hitch. A mounting bracket is recommended to keep this connector secure. Now, this does not include a mounting bracket, but I do have one on your screen that you could take a look at and you could add to your order. As you can see, I have the item number there on your screen for that mounting bracket, and that's just going to be a very convenient way to have this always accessible at the back of your vehicle. Now, the maximum amperage for the stop turn lights is 5.0 amps per circuit, and for the taillights it's 7.5 amps per circuit. And a great set of instructions are included to walk you through the insulation process. You're also going to get a small tube of black silicone and it is also recommended that you use a small amount of dielectric grease on all of your electrical connections, like your plugs on the vehicle and the four pole connector itself. It's designed to help prevent electrical failures caused by corrosion and moisture. So, on your screen, I am including our item number for a small tube of dielectric grease. And again, you can just take that item number and put it in the search field of our website and it will take you to that grease and you can add that to your order. Well, that's gonna conclude our look today. I do hope that it was helpful for you. Again, my name is Andy. Thank you for joining me.

Customer Satisfaction Score:

Ratings & Reviews

5.0

8 reviews
Review sort icon
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.

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No problems, went together fairly easy but took some time.



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works great easy install



by:

The delivery of my order was excellent. I received both items I ordered quickly.
I will continue to use their service and suggest them to anyone that needs trailer parts



by:

Excellent quality, easy installation. I haven't used on a trailer yet its just to keep for an emergency.


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See what our Experts say about this CURT Custom Fit Vehicle Wiring

  • Recommended Hitch for a 2024 Mitsubishi Outlander Sport
    Yes, it does Nichole. I checked with Curt and their item # C13079 hitch has been confirmed to fit all models of the 2024 Mitsubishi Outlander Sport including the Trail edition. This is a class III hitch with a 2" receiver. It is custom fit and comes with all necessary hardware to complete the installation. What are you going to be using the hitch for?
    view full answer...
  • Recommended Wiring Harness for a 2021 Mitsubishi Outlander Sport
    The correct wiring harness for a 2021 Mitsubishi Outlander Sport is the Curt T-Connector Vehicle Wiring Harness item # C37NR. This custom-fit T-connector plugs into your Outlander's wiring harness, which is located behind your tail lights. It will provide you with a 4-way connector that will control your trailer or accessories lighting functions. I recommend using the No-Drill Mount Bracket item # 18136 and the item # C42CR to secure the 4-way connector to your hitch. This will put it...
    view full answer...
  • 4-Way Trailer Wiring For 2024 Mitsubishi Outlander Sport
    The correct 4-way trailer wiring for your 2024 Mitsubishi Outlander Sport is the following from Curt: - Curt T-Connector Vehicle Wiring Harness # C37NR
    view full answer...
  • Recommended Hitch for a 2024 Mitsubishi Outlander Sport?
    Yes, I can! To add a hitch to your 2024 Mitsubishi Outlander Sport, I recommend the etrailer item # e63AR. This hitch is custom fit and bolts to your Outlander with included hardware. It is a class III hitch with a 2" receiver so it'll be great for towing, bike racks, and cargo carriers. It has a 3,500 lbs towing capacity and a 350 lbs maximum tongue weight. If you are planning on towing you will also need a wiring harness item # C37NR and a ball mount kit item # C45534.
    view full answer...
  • Does the Curt Hitch C13079 Fit a 2024 Mitsubishi Outlander Sport?
    Yes, it does! The Curt Hitch item # C13079 has been confirmed to fit the 2024 Mitsubishi Outlander Sport. This is a class III hitch with a 2" receiver so it'll be great for towing, bike racks, and cargo carriers. It has a 3,500 lbs towing capacity and a 350 lbs maximum tongue weight. I have linked an installation video below so you can see how to get it set up. If you are planning on towing you will also need a wiring harness item # C37NR and a ball mount kit item # C45534.
    view full answer...

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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Wilson B
Updated by:
Wilson B
Employee Andy C
Installed by:
Andy C
Employee Sabrina W
Written by:
Sabrina W

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