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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 # C56405
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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. 1-800-940-8924 to order CURT custom fit vehicle wiring part number C56405 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 (9)
  • Q & A (0)
  • Photos
  • Why etrailer?

CURT Custom Fit Vehicle Wiring - C56405

  • 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 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: 5.0 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 behind the driver's-side and passenger's-side tail lights. You will have to remove all trunk floor coverings, rear scuff panel, and interior side trim panel, and pull back the felt trunk liner to access these connection points. Once you've plugged in the T-connector, run the hot lead to your car battery, which can be found in your trunk on the passenger's side. 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.

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.

56405 Curt T-Connector - Surface Mount Technology - 4 Wire

Installation Details C56405 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 - C56405

Average Customer Rating:  4.9 out of 5 stars   (9 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.


Excellent, great fit. The only reason for 4 stars instead of 5 is that I would have preferred not having to run a power line all the way to the battery at the front of the car. It always makes me feel a bit sketchy that the wire will catch on something even though there were plenty of zip ties to secure it. Also by having the power line it is immediately apparent that there was electrical work done to the car which can potentially void the factory warranty if there is an electrical failure.

Thank you for your review. As long as you keep the wiring away from moving parts and heat with a lot of zip ties then you shouldnt have any issues. There is a law called the Magnussen-Moss warranty act that states, in part, that if you install an aftermarket part on your car then it will not void the warranty unless that part caused the problem.
-- Etrailer Expert Heather A - 06/23/2021


VW GTi 2020 install was a snap what a headache remover just gonna rewire the trailer and plug n go. VW dealer couldn’t help me out wanted to send me to an RV Shop to get fixed up. That’s when I did some searches n etrailer popped up and all my troubles are gone DYI easy peasy ready to roll n tow


Perfect fit


Excellent customer service Thank you An drew

Volkswagen GTI

PERFECT for my 2020 GTI. Easy install and works a charm.


One Year Later...
The light kit is still
working just fine. Can't complain at all.

2020 Volkswagen Golf


2018 Volkswagen Golf


Ask the Experts about this CURT Custom Fit Vehicle Wiring

  • Can the Rear 12 Volt Socket on a 2018 Volkswagen Golf be Used to Power a Trailer Light Harness
    I really wish that I could tell you that the 12 volt power source you have in the rear compartment of your 2018 Volkswagen Golf is suitable for the Curt T-Connector Vehicle Wiring Harness part # C56405 but it is not. The keyed circuit is not the issue but rather the power draw of the harness. This harness requires a 15 amp fuse and as you mentioned the power source in your rear compartment is only 10 amps. Therefore, it is very likely that with multiple signals active like the running lights...
    view full answer...
  • Will The Curt Hitch And Wiring From A 2020 VW Jetta Also Fit A 2021 VW Jetta?
    I will start by saying that the Curt Hitch # C11540 will fit the VW Jetta line from 2019 to 2021 as long as it is not a GLI model and or with dual exhaust. As long as don't have one of these, you are good to go. The wiring is a different matter though. I checked with Curt and they do not offer a custom fit wiring harness for this year range of Jetta, so I recommend going with the Tekonsha T-One Vehicle Wiring Harness # 118791. This is a direct plug an play kit, but you will need to run...
    view full answer...
  • Recommended Trailer Wiring Harness For A 2016 Volkswagen Golf GTI Mk7
    Though The Curt harness # C56405 is not confirmed for you 2016 Volkswagen Golf The Upgraded Heavy Duty ModuLite Circuit Protected Vehicle Wiring Harness with Installation Kit # 119190KIT is confirmed. This modulite harness includes the circuit protection to safeguard itself and the tow vehicle from harmful electrical shorts and mis-wire situations. This harness powers the trailer's stop, turn, tail and running lights directly from the tow vehicle's battery. This harness will work on...
    view full answer...
  • Correct Size Fuse for Curt T-Connector Vehicle Wiring Harness On 2018 - 2020 VW Golf GTI
    The Curt T-Connector Vehicle Wiring Harness part # C56405 which is a fit for a 2018 - 2020 Volkswagen Golf GTI uses a 15 amp fuse. Please keep in mind we do offer the Curt Powered Converter Wiring Kit part # C55152 which is a replacement power line kit that has the fuse you need.
    view full answer...
  • Trailer Hitch For 2019 Volkswagen Golf GTI That Does Not Require Fascia Trimming
    The hitch option for the 2019 Volkswagen GTI that does not require trimming or modifying the bumper is the EcoHitch Stealth Trailer Hitch Receiver part # 306-X7375. However, this installation may require possible minor exhaust modification, it does not require bumper or fascia trimming. We do not carry an option that does not require some type of trimming whether it be bumper or exhaust on the GTI. The Stealth hitch is a great option visually because is it completely hidden once installed....
    view full answer...
  • Trailer Hitch Recommendation for 2018 Volkswagen Golf GTI
    For your 2018 Volkswagen Golf GTI the hitch I recommend is the Curt hitch part # C11412 because the hitch has enough towing capacity for a small trailer and is made in the USA. I attached an install video link to this page for you to check out as well. For a ball mount Curt requires the ball mount part # C45521 and then the hitch balls part # A-82 for a 2 inch ball or # A-80 for a 1-7/8 inch ball. For trailer wiring the Curt wiring harness part # C56405 is recommended as it is a custom...
    view full answer...
    Image 1 for
  • Wiring Harness and Hitch Recommendation for 2019 Volkswagen Golf GTI Rabbit
    We do have a 4-pole flat trailer connector for the 2019 Volkswagen Golf GTI Rabbit but the part # 118787 does not fit. The wiring harness you need is Curt 4-pole flat part # C56405. We installed the Curt wiring harness on a 2018 Volkswagen Golf GTI. Since the 2019 GTI Rabbit is just a trim package upgrade, the wiring harness fits the same. I have attached a video for your reference. If you need a hitch for the Rabbit, I recommend EcoHitch part # 306-X7375. The EcoHitch's cross tube is...
    view full answer...
  • Trailer Hitch Recommendation for 2018 Volkswagen Golf GTI
    For your 2018 Volkswagen Golf GTI the Curt hitch part # C11412 is a confirmed fit and would be the hitch I recommend. It is a USA made hitch that is custom fit for your vehicle with great towing weight capacities. For trailer wiring you'd then want the Curt part # C56405 which is also a confirmed custom fit that won't require any splicing or hardwiring. For a ball mount you'd then want the part # C45521 and for hitch balls you'd want the part # A-82 for a 2 inch ball or part # A-80 for...
    view full answer...
  • Is Trimming Required on the Draw-Tite Hitch for 2018 Golf GTI Autobahn
    I checked the installation instructions on the Draw-Tite Sport Frame Hitch Receiver # 24979 and there will be some minor trimming of the fascia required during the installation. It also notes that you'll have to disconnect the backup sensors during the installation, but it won't interfere with it functioning once the hitch is installed. We haven't completed an installation of the Draw-Tite # 24979 hitch on a 2018 GTI, but we have installed the EcoHitch # 306-X7375 and the installation processes...
    view full answer...
  • Fixed Ball Mount for 2018 Volkswagon Golf
    I would be glad to make a recommendation and help you set up a ball mount for your 2018 Volkswagen Golf. I recommend the Curt Ball Mount for 2" Hitches - 5" Rise, 6" Drop - 8,000 lbs - Aluminum item # C24WR. You will also need a hitch ball the Curt 2" Hitch Ball item # A-82 is 2 3/4" tall. This ball and ball mount fits your EcoHitch item # 306-X7375 2" hitch receiver and has a 5" rise. I recommend the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector Item # C56405....
    view full answer...
  • Trailer Hitch for 2018 VW Golf GTI Autobahn with Parking Assistance
    I have a good solution but the EcoHitch Hidden Trailer Hitch Receiver part # 306-X7332 is not a fit for your 2018 VW Golf GTI Autobahn. That is specifically for the R model of the Golf. Instead use the EcoHitch Stealth Trailer Hitch Receiver part # 306-X7375. This hitch is designed for your vehicle and offers the removable receiver tube so you can have a very nice clean look if you choose to when the hitch is not in use. As far as the parking assist there have been no reports of the hitch...
    view full answer...
  • Best Trailer Hitch for 2018 VW Golf
    The best trailer hitch for your 2018 VW Golf is the Curt # C11412 because it does not require any trimming of the rear fascia on your vehicle unlike the Draw-Tite # 24925 hitch which does require it. The Curt hitch does have a more visible crosstube than the Draw-Tite but not having to cut off part of your vehicle's trim is a worthwhile trade-off. To add wiring which will give you a 4-way connector and allow you to power your trailer's lights you need Wiring Harness # 118646 unless your...
    view full answer...
  • What is the Height From Ground to the Top of Drawbar on 2018 VW Golf GTI?
    The Draw-Tite Sportframe Trailer Hitch Receiver # 24979 will have a height of approximately 13" to the inside top of the receiver tube on your 2018 VW Golf GTI. The center of the bolt hole will sit approximately 4" from the outermost point of the rear bumper. The T-One Vehicle Wiring Harness # 118787 is only confirmed to fit the Golf R Models. For your GTI you will need the Curt T-Connector Vehicle Wiring Harness # C56405 for a 4-way flat connector. The EcoHitch Hidden Trailer Hitch...
    view full answer...
  • Can Trailer Hitch be Installed on 2019 Volkswagen Golf TSI
    What you are referring to is actually pretty common when it comes to smaller vehicles. It isn't surprising to see that UK versions are given the thumbs up to tow while US versions are discouraged from towing and I'm not sure what the reason is. I will say that quite a few people do still get trailer hitches installed on their Volkswagen Golf and are just fine. I can't really go against what your owner's manual says but if you do decide to install a trailer hitch the Curt Class I part #...
    view full answer...

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Info for this part was:

Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video Edited:
Chris R
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 Jonathan Y
Video by:
Jonathan Y
Employee Michael B
Video by:
Michael B

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