bing tracking image
  1. Custom Fit Vehicle Wiring
  2. CURT
  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 4 Flat
  6. Powered Converter
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 # C56404
lowest price pledge
Retail:$113.99
Our Price: $74.85
You Save: 34%
Custom Fit Vehicle Wiring

Will this fit?

To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.

Orders above $99 qualify for Free Shipping
Shipping Weight: 1.33 lbs
Quantity: 
In Stock
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

Customer Photos

Need help with installation?
Locate installers near me
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 C56404 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.
  • All Info
  • Reviews (24)
  • Q & A (0)
  • Photos
  • Why etrailer?

CURT Custom Fit Vehicle Wiring - C56404

  • 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.


Features:

  • 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


Specs:

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


Installation

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, sub woofer, spare tire, 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 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.



56404 Curt T-Connector - Surface Mount Technology - 4 Wire

Installation Details C56404 Installation instructions

This Product Fits The Following Vehicles





Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C56404

Average Customer Rating:  4.6 out of 5 stars   (24 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.

by:
Audi Q5

Installation was decently straight-forward (as much as anything can be with an Audi) and sits nicely. I'm very pleased with how low-profile this hitch is. A great choice if you're looking to tow with your Q5. I will recommend accounting for how low the receiver is when you buy your ball hitch.



by:

I installed the Curt trailer wiring kit right after I installed my hitch, so some of the access points were already open. If you follow directions and install the converter in the battery compartment, the wiring harness to the tail lights will be too short. I installed the converter in the driver side compartment where the air compressor rides and ran the power wire only to the battery compartment. This provided barely enough length to reach the tail light wiring connectors in the lift gate. Other than that, I followed the directions and everything looks good, all the wiring is hidden behind trim panels, and the harness works great.



by:

I did end up using it, but the install is ridiculous. I took it to the Dealer and paid ~ $500 to have it installed. The directions show routing the wires up side thru roof and into lift gate lites. And you have to dissasemble the lift gate door panels, Crazy. Even the dealer did something much simpler.


Comments
The installation for this harness is a detailed installation. I recommend downloading the manual from the product page as it will give step by step instructions so that you determine the difficulty.
-- Etrailer Expert Jenny N - 03/22/2022

by:

All in all, it was a very simple install for both the hitch and the lights. Would highly recommend. I do think they could have packaged it a little better, it broke through the box in shipping, but it’s a heavy hitch, so it is what it is.



by:
2015 Audi Q5

Product is great, instructions are well done. When installing however, the driver's side wiring was not long enough to mount the unit in the battery well as depicted in the instructions, and the passenger-side wiring length only allowed the wiring to be routed under the trim along the top of the hatchback (not along the scuff plate at the back of the car). The CURT instructions should be updated to make this clearer.



by:

Works as advertised. Pretty simple install. As usual great quality product(s) from etrailer



by:

Flawless instructions and has worked great for over a year! Needs a bracket for the plug!



by:

Fast and easy install and the price was great



by:

Be aware that the trailer lights do not work with the hatch open but otherwise easy to install and functions as intended.



by:

It didn’t work for my q5. Shop said I needed a modulator, which Audi no longer makes.


Comments
It sounds like the shop you took this to was recommending a wiring harness with a ModuLite which offers peace of mind by including circuit protection to safeguard itself and the tow vehicle from harmful electrical shorts and mis-wire situations. We do have a wiring harness that has this protection, item # 119190KIT
Upgraded Heavy Duty ModuLite Circuit Protected Vehicle Wiring Harness with Installation Kit
$110.66
.
-- Etrailer Expert Sierra K - 12/02/2021

by:
2014 Audi Q5

This kit worked great on my 2014 Audi Q5. If you are a DIY type, you should be able to accomplish the install fairly easily



by:

I purchase the product and I try it and it was great. I didn't use it a lot of times but all the connectors was fitting very good and it is almost like factory one. That was my goal to be as closest as possible to the factory.



by:
2015 Audi Q5

Have not installed yet but looks to be an easy install as instructions seem to be pretty clear



by:

Great harness. Take your time for a clean install. I put the hub of the harness by the wheel well.



by:

This harness uses factory original plugs that interface with the vehicle's original wiring harness to make installation a breeze, quite straightforward and seamless. No janky scotchlocks, crappy crimps or poor "splice" jobs to be had here. Some disassembly required, but all the best wiring jobs do. 100% would recommend for the professional installer, although this project may be above the heads of the inexperienced DIYer.



by:

Install was super easy!



by:



by:



by:



by:



by:
2014 Audi SQ5



by:
2015 Audi Q5



by:



by:



by:


25
25

Ask the Experts about this CURT Custom Fit Vehicle Wiring

  • Passenger Side Taillight not Illuminating After Installing Curt Wiring On Audi Q5
    It sounds like you have a classic ground issue with the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer part # C56404 on the 2016 Audi Q5. When the wiring harness does not have a good ground connection it will make the functions act erratically. Some functions will illuminate while others won't. I recommend to take a look at your ground connection and make sure it is attached to a clean bare metal surface of the vehicle's frame. Also please keep in mind this wiring harness...
    view full answer...
  • Troubleshooting Curt Trailer Wiring Harness Installation on 2017 Audi Q5
    The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56404 is a confirmed fit for your 2017 Audi Q5 and fits behind both the driver and passenger side rear access panels. I've attached the installation instructions which gives you photos to see the locations. The wires will be long enough when installed correctly. I confirmed this with Curt.
    view full answer...
  • Will the Curt T-Connector Vehicle Wiring Harness C56404 Fit a 2013 Audi Q5 Hybrid
    The Curt T-Connector Vehicle Wiring Harness part # C56404 is a confirmed fit for a 2013 Audi Q5 Hybrid. It offers plug-n-play installation as well so there will be no splicing into any wires on the vehicle. It provides a standard 4-way flat trailer connector that has all the basic trailer lighting functions. If you don't already have a trailer hitch, the Draw-Tite Trailer Hitch Receiver part # 75940 is what I recommend because of the hidden cross tube. It offers bolt-on installation as well.
    view full answer...
  • Trailer Wiring that Fits 2014 Audi Q5
    Yes we have trailer wiring harnesses that fit your 2014 Audi Q5 like the Curt # C56404 which installs easily by plugging in line with the taillight wiring of the vehicle.
    view full answer...
  • Is There a Plug and Play Trailer Wiring Harness for a 2011 Audi Q5
    I do have an option for you but there are no plug-in play trailer wiring harness options for a 2011 Audi Q5. The Curt T-Connector Vehicle Wiring Harness you referenced is not a fit so if you're having issue that is likely why. I recommend the ZCI Circuit Protected Vehicle Wiring Harness part # 119250KIT which uses clamp-on sensors therefore no splicing is required. Please note, you should be testing the wires to use with the hatch closed.
    view full answer...
  • Recommended Trailer Hitch and Wiring for 2014 Audi Q5 Hybrid
    I recommend using the Curt # C13136 on your 2014 Audi Q5 Hybrid, which will provide you with a 2" hitch receiver that is well suited for towing a trailer. It looks like your Q5 hybrid has a 4400-lbs towing capacity, so you'll want to make sure that you stay under that to avoid damaging your vehicle, but this hitch will allow you to tow up to that capacity. Since you're going to be towing, you'll also need trailer wiring, a ball mount and hitch ball to complete your towing setup. For wiring...
    view full answer...
  • Installation Process for Curt 13136 Hitch for 2014 Audi Q5
    Because of where all hitches are going to need to attach to on your 2014 Audi Q5, removal of the rear bumper is going to be a required step regardless of what hitch you're installing; unfortunately there's no way around this. While the process may seem daunting at first glance, it's not terribly complicated and when done with care and patience, you can avoid damaging the bumper. If you're going to be towing with this hitch, you'll also need trailer wiring, a ball mount, hitch ball, hitch...
    view full answer...
  • Wiring Harness Fit For 2014 Audi Q5 Premium
    While we do have a trailer wiring harness for your 2014 Audi Q5 Premium, I checked with Curt and the part you mentioned is not a fit. Instead, the correct wiring harness for your Audi is the following: - Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56404 I verified with Curt that the # C56404 is compatible and will fit your '14 Audi Q5 Premium so you can power your trailer lights. It will work perfectly in conjunction with the hitch that fits your car,...
    view full answer...
  • Best Trailer Wiring Options for 2017 Audi Q5
    For your 2017 Audi Q5 you'd want the version of the trailer wiring harness you referenced that comes with the power wire you'd run up to the battery with the part # 119190KIT but technically the # 119190 would work too but you'd need to run additional wire to the battery. I attached an install video link for this for you to check out on a very similar 2016 Q5 as well. Not to make your choice any harder but the best option is the Curt harness # C56404 which is custom fit instead of universal...
    view full answer...
  • Recommended Brake Controller and Wiring for 2017 Audi Q5
    We have exactly what you need, and I strongly recommend going the wireless brake controller route on your 2017 Audi Q5 so that you don't need to splice into any existing wiring or run wiring into the cabin of the vehicle; this is especially helpful considering the sensitivity of the electrical systems in Audi and other European vehicles. Since you've already got a Curt T-Connector # C56404 installed you'll just need to add the # ETBC7L to give you a 7 way wiring harness for your Q5 that...
    view full answer...
  • How To Secure Curt Echo On 2015 Audi Q5
    The best option to secure a trailer connector on a 2015 Audi Q5 with a trailer hitch like the Draw-Tite Max-Frame Trailer Hitch Receiver part # 75940 is the Curt Easy Mount Bracket part # C58000. This will provide a safe and secure connection for the 7-Way RV Upgrade Kit part # ETBC7L and Curt Echo Wireless Trailer Brake Controller part # C51180. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # C56404 is an excellent option as well.
    view full answer...
  • Parts Needed To Tow a Trailer With Brakes Using a 2014 Audi Q5
    In order to tow a trailer with a 2014 Audi Q5 you'll need a trailer hitch, trailer wiring harness, brake controller (if applicable), and ball mount/hitch ball. The Draw-Tite Max-Frame Trailer Hitch Receiver part # 75940 is a great option to start with. For the trailer wiring, the Curt T-Connector Vehicle Wiring Harness part # C56404 is what I would start with as it can then be adapted to a 7-way using the Trailer Brake Controller Install Kit part # ETBC7L. This setup will then work perfectly...
    view full answer...
  • Installing 7-Way Connector and Brake Controller on my 2014 Audi Q5
    If you currently have a working 4-Way plug then using the 7-Way RV Upgrade Kit for Trailer Brake Controller Installation Kit part # ETBC7L kit is a great way to get a powered 7 Way connector on the rear of your 2014 Audi Q5. You can use the Curt No-Drill Bracket part # C57202 to attach the 7-Way to. The bracket will mount around the tube of your hitch and really does a great job staying solid. With this kit using the Curt Echo part # C51180 is an easy way to add a brake controller that...
    view full answer...
  • Parts Needed to Convert 4-Way of 2014 Audi Q5 to 7-Way to Tow 2021 Sunset Park RV Sunray 109E
    If your trailer does not have brakes all you would need is the part # ETBC7L as an adapter to convert the 4-way to a 7-way and run the 12 volt power circuit. If you do have trailer brakes you would need the # ETBC7 instead of the # ETBC7L and a brake controller. This kit comes with everything needed to wire up the 7-way and install a brake controller. For a brake controller I would recommend the Brake EVN # TK63VR. This is our best selling brake controller because of how well it works...
    view full answer...

Do you have a question about this Custom Fit Vehicle Wiring?




  • Why etrailer.com?

    At etrailer.com we guarantee:
  • Highest quality custom fit vehicle wiring for the best price.

    Our Lowest Price Pledge ensures you will never overpay for the parts you need.
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate custom fit vehicle wiring information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jameson C
Expert Research:
Jameson C
Employee Kathleen M
Video Edited:
Kathleen M
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

At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.