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 # C56338
lowest price pledge
Our Price: $30.24
You Save: 48%
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: 0.88 lbs
In Stock
Curt Trailer Hitch Wiring - C56338
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

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs into OEM tow package wiring harness. Powered converter reduces strain on wiring system. SMT construction ensures superior performance. Call 800-298-1624 to order Curt custom fit vehicle wiring part number C56338 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 (13)
  • Q & A (2)
  • Videos (1)
  • Photos
  • Why etrailer?

Curt Custom Fit Vehicle Wiring - C56338

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

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs into OEM tow package wiring harness. Powered converter reduces strain on wiring system. SMT construction ensures 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 - no cutting or splicing of wires
    • Locate connection point in rear cargo area
    • Plug in T-connector
  • 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: 3 amps per circuit
    • Tail lights: 6 amps per circuit
  • 1-Year limited 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 coverings, storage trays, and scuff panel to access this harness. Once you've plugged in the connector, open your fuse box and locate the fuse position indicated in the instructions. Then insert the included 15-amp fuse.

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.

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.

56338 Curt T-Connector - OE Replacement 4-Flat - Surface Mount Technology

This Product Fits The Following Vehicles

California residents: click here

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 Curt Custom Fit Vehicle Wiring - Trailer Hitch Wiring - C56338 Review

Speaker 1: Today we're taking a look at a Curt T-Connector Vehicle Wiring Harness with a Four-Pole Flat Trailer Connector. Now this product is designed to fit certain years of the Mazda CX-9. To ensure or double check that this is a fit for your vehicle, you can always use the vehicle fit guide which is located at etrailer.com.Once installed, this unit provides a four-way flat trailer connector at the back of your vehicle, to power your trailer's signal lights. This is compatible with five-pole, six-pole and seven-pole adapters. Adapters are sold separately. And it comes with a dust cap for the four-way flat connector.

That way you can cover up the connection points whenever your plug's not being used.The black box right here, is the included tail light converter. This ensures that your vehicle's wiring matches out of your trailer. So the power module connects directly to your vehicle battery through the wiring, to avoid overloading the vehicle's electrical system.We're looking at a nice, durable construction. This is constructed using surface mount technology for consistent, reliable performance. What that does, is it simply maximizes the trailer light yield and intensity, while producing minimal heat and it ensures superior operation, even in rough road conditions.Now the installation is quick and easy.

There's not cutting or splicing of wires needed. All you need to do is look at the connection point in your rear cargo area and plug in your T Connector. This plug is custom fit for the port on the vehicle, so they match up perfectly and they snap lock together for a nice, tight, secure fit.Once you have that plugged in, you'll need to mount your converter box to a safe, out-of-the-way location. You can do that using the double sided, adhesive foam tape provided in the kit. And you could also use one of the cable ties.

They have one large cable tie here, which can be used for that purpose.Once you have that done, you can go ahead and route this where you want it. Now some people choose to keep this stowed in the vehicle, and then just extend it out the rear hatch when they need to use it. In those situations you wanna be sure to stay away from the latch area when the rear hatch closes. A lot of times you can find an access hole in the bottom pan of the cargo area to route this through and then out towards your hitch. In which case, you would need a mounting bracket.

So you've got a couple different options available. It just really comes down to personal preference.But once you have it the way you want it, they do include some cable ties right here. That way you can secure any excess wiring up and out of the way. Really cleans up your installation, keeps your wires safe. It is recommended that you use a small amount of terminal grease or dielectric grease on all your electrical connections. Like the plugs on the vehicle and the four-pole connector itself. That grease is specifically designed to help prevent corrosion to the connection points.It comes with a 10 amp fuse right here, which goes into the fuse holder that's located here on the wiring harness. When it comes to the maximum amperage for the stop and turn lights, we're looking at 3 amps per circuit and for the tail lights, six amps per circuit.That's gonna do it for today's look at the Curt T-Connector Vehicle Wiring Harness with a Four-Pole Flat Trailer Connector.

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C56338

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 into OEM tow package wiring harness. Powered converter reduces strain on wiring system. SMT construction ensures superior performance.

- C56338
2018 Mazda CX-9

Part got here on time, and fit easily, even easier than the video due (I think) to Mazda putting the ground wire in the connection. All I had to do was put the connector in, then test it. Worked great. My car is a 2018, and the video is for a 2016, but it is the same as far as taking the panels off.

Great, no problems.
Steve D - 05/30/2020

- C56338

Item came as described. Installation was made manageable with video instructions.

- C56338
2020 Subaru Outback Wagon

Plug for this device was well hidden behind the rear passenger interior trim. Finally found it but it was not as ‘accessible’ as I would have thought. Grommet under the spare tire is perfect for running the trailer plug through

- C56338

Plug and play great quality products

- C56338
2017 Mazda CX-9

Ordered a trailer hitch and wiring harness for my Mazda CX-9. Complete order received in just a few days, instructions were accurate and easy to follow, installed both the hitch and wiring harness by myself in 2.5 hours. Very satisfied. P.S. trailer installation video was very helpful.

- C56338

After a year, everything's as good as the day I installed it. No problems whatsoever on my Mazda CX-9.

- C56338

The wiring harness was easy to install and works great. My only hiccup is that the install video does not exactly match the harness. Mine came with no need to run the ground wire. It is already wired directly into the loom. Also, instead of running the harness through the trunk and leaving it in trunk, I drilled out a plastic grommet next to the car’s harness and ran it out and down the inside of the rear quarter panel.

- C56338
2017 Mazda CX-9

As usual, perfect fit. Thanks etrailer.

- C56338

- C56338


- C56338
2019 Mazda CX-9

Easy easy easy! Works great and easy to install

- C56338
2016 Mazda CX-9

- C56338
2016 Mazda CX-9



Ask the Experts about this Curt Custom Fit Vehicle Wiring

  • Wiring Harness and Hitch Recommendation for 2016 Mazda CX-9
    The term 'Towing Package' is pretty useless because it's an extremely vague description whose meaning varies from vehicle manufacturer to vehicle manufacturer, and even among different models from the same manufacturer. For the sake of this discussion in terms of a wiring harness, Tekonsha uses the term 'tow package' because there is a single, dedicated connector for connecting a trailer harness, rather than installing inline where the factory taillight harness connects to the taillight...
    view full answer...
  • Ground Wire on Curt T-Connector for 2018 Mazda CX-9
    The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56338 does not have a separate ground wire outside of the connector. You do not need to find an additional ground you will simply utilize the integrated ground in the quick connect just like the power for the converter. It is simply a plug and play harness. Connect quick connect to vehicle side harness, mount the converter, and run the 4-way to your desired location...don't forget the fuse on the power wire.
    view full answer...

  • 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 Mike L
Expert Research:
Mike L
Employee Lindsey S
Edited by:
Lindsey S
Employee Cole B
Installed by:
Cole B
Employee Kristina F
Written by:
Kristina F
Employee Isabelle B
Updated by:
Isabelle B

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.

Product Experts Available Now!
Call 800-298-1624