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  1. Custom Fit Vehicle Wiring
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  4. Trailer Hitch Wiring
  5. 4 Flat
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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 # C56374
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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. 1-800-496-5010 to order CURT custom fit vehicle wiring part number C56374 or order online at 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.
  • All Info
  • Reviews (13)
  • Q & A (0)
  • Photos
  • Why etrailer?

CURT Custom Fit Vehicle Wiring - C56374

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • Powered 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 in rear cargo area
    • Plug in T-connector
    • Run hot lead to car battery
  • Includes a powered tail light converter that connects directly to your battery to avoid overloading your 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 rear cargo area. You will have to remove the trunk floor covers, storage trays, scuff panel, and interior side 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 cargo area.

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.

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.

56374 Curt T-Connector - Surface Mount Technology - 4 Wire

Installation Details C56374 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C56374

Average Customer Rating:  4.8 out of 5 stars   (13 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.


Product itself is decent, does the job. Install can be challenging, mainly the power wire. I was able to run the power wire to the battery through the cabin. There are YouTube videos that show you how to find the fire wall access point. This way you can bypass running the wire underneath the car if you don’t have a lift or don’t want the wire exposed to the elements.


Product was great, It installed just as the video's I watched said it would. Packaging: The box was beat to death due to the weight of the hitch. The hardware was loose in the box. It was all there, how I don't know because there were large holes in the box. It would have been much better if the hardware bag was taped to the hitch itself. I have used it to pull my kayak trailer and a bicycle rack. Good product.


Everything looks good. However, while there is a schematic drawing of the wire going from the back of the car to the positive terminal at the front, there is no clue as to how to route it there.

Thank you for your review. We have a video of the wiring installation that shows what the best route is:
-- Etrailer Expert Sierra K - 09/24/2021

2017 Volkswagen Passat

Again, ordered for my 2020 Passat but none of the connectors matched and the box it came in said it was for 2017. My son used it on his 2014 Passat. Easy to install and works great


No splice plug in connectors are the only way to go!! However the hardest part is running hot feed wire to battery but not THAT bad...

2015 Volkswagen Passat

Fast Delivery. The installation took me a little while but if you follow the directions this assembly will install fairly quickly.
Everything seems to work very well!



2013 Volkswagen Passat

Nice one



2015 Volkswagen Passat

2013 Volkswagen Passat


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

  • Trailer Hitch Recommendation for Use with Curt Hitch on 2013 Volkswagen Passat
    Our trailer hitches like the Curt part # C112321 do not come with trailer wiring but this one does come with a ball mount. For trailer wiring you'd then want the Curt harness part # C56374 and you'd be set.
    view full answer...
  • Recommended Trailer Wiring Harness for a 2016 Volkswagen Golf R
    I do have an option for you but the ZCI Circuit Protected Vehicle Wiring Harness part # 119250KIT is not recommended for use on your 2016 Volkswagen Golf R. Instead, you will want to use the Curt T-Connector Vehicle Wiring Harness part # C56374 which is actually a plug and play option that will not require you to cut or splice any wires like the original harness you inquired about does. With that being said, in order to hardwire a harness into your vehicle you would need to use a circuit...
    view full answer...
  • 4-Way Flat Vehicle Wiring Harnesses For a 2013 VW Golf GTI
    The Curt Tail Light Converter that will fit your 2013 Volkswagen Golf TDI is the Converter # C56236, which will require you to splice into your tail light wiring. The Curt T-Connector # C56374 is only confirmed to fit the following vehicles and not your Golf GTI. 2012 - 2015 Volkswagen Passat 2014 - 2015 Volkswagen Passat 1.8L I4 Engine - Turbocharged 2012 - 2015 Volkswagen Passat 2.0L I4 Diesel Engine - Turbocharged and 3.6L VR6 models 2012 - 2013 Volkswagen Passat 2.5L I5 Engine 2017...
    view full answer...
  • Is a Wiring Harness Included with the EcoHitch # 306-X7332 for a 2017 Volkswagen Golf R
    The EcoHitch Hidden Trailer Hitch Receiver # 306-X7332 only comes with the trailer hitch itself, but for wiring we have the Curt # C56374 which fits the R model of your 2017 Volkswagen Golf. If you are looking to tow with your VW Golf then you will also need a ball mount, hitch ball, and hitch pin and clip. I recommend the Curt Kit # C45036 which comes with all of these components but you will want to check out the linked ball mount article to ensure that the 2" drop is correct for your...
    view full answer...
  • Recommended Trailer Hitch and Wiring for 2014 VW Passat 2.5L
    The trailer hitch I recommend for a 2014 Volkswagen Passat 2.5L is the Curt Trailer Hitch Receiver part # C11232. This trailer hitch has a class I rating with 1-1/4" opening. It works great for towing or hitch mounted accessories. In order to add wiring, I recommend the Curt T-Connector Vehicle Wiring Harness part # C56374. This is a plug-in-play kit with no splcining. In order to complete your setup you'll also need the following: Curt Drawbar part # C45520 Curt Hitch Pin and Clip part...
    view full answer...
  • Recommended Trailer Hitch for 2018 VW Golf R Model
    I reached out to my contact at Curt and they have not yet tested the fit on your model. It is very likely that the Curt Trailer Hitch Receiver C11475 will fit your vehicle but the fit has not yet been confirmed. For the only confirmed fit we have for your 2018 VW Golf R model, I recommend the EcoHitch # 306-X7333. I've attached the installation instructions to help. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56374 is also a very likely fit that...
    view full answer...

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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Joshua S
Video Edited:
Joshua S
Employee Dustin K
Video Edited:
Dustin K
Employee Cole B
Installed by:
Cole B
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Isabelle B
Updated by:
Isabelle B
Employee Ronnie R
Written by:
Ronnie R
Employee Shane H
Test Fit:
Shane H
Employee Jacob H
Video by:
Jacob H

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