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  1. Custom Fit Vehicle Wiring
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  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

Our Price: $47.14
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Custom Fit Vehicle Wiring

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Shipping Weight: 1.66 lbs
56043 - 4 Flat CURT 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. 1-636-242-8008 to order CURT custom fit vehicle wiring part number 56043 or order online at 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 (1)
  • Q & A (0)
  • Videos (2)
  • Photos

CURT Custom Fit Vehicle Wiring

  • 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 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
  • Limited 1-year warranty


This custom-fit T-connector plugs into your vehicle's wiring harness, which is located behind the driver's-side interior trim panel in your rear cargo area. 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.

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.

56043 CURT T-Connector - Surface Mount Technology - 4 Wire

Item # 56043

Installation Details 56043 Installation instructions

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 - 56043 Review

Today we're going to review part number 56043, this is the Curt key connector vehicle wiring harness with the 4-way flat trailer connector. This wiring harness is a custom fit part, it is designed to fit the 2003 to 2007 Cadillac CTS vehicles. With a custom fit part, I always recommend to go to our website, use our fit guide, put in your year and model vehicle and it will tell you if this will work for your application. Now this harness provides this 4-way flat trailer connector in the back of your vehicle to power your trailer signal light. Connects very quickly and easily, just locate your connection point which is in your rear cargo area, plug in the T-connector right here, ground your white wire, run your power wire to your vehicles battery and you'll be all ready to go. That does include this tail converter, this black box right here to ensure your vehicles wiring match the head of your trailer. This is a power module converter, that means it connects directly to the battery, using this power wire, the reason they do that is to avoid overloading your vehicle's electrical system. The converter box right here, the black box is constructed using SMT technology which is surface mount technology. This will give you consistent, reliable performance, helps maximize your trailer light, yield and intensity while producing minimal heat and ensures superior operation in any rough road conditions. This part also comes with a nice dust cap for your 4-way, so what you can do is just attach this to your 4-way plug and you can leave it on there if you like, but what's nice is when you're not plugged into the trailer you can just put your cap over the terminals, protect it from any damage or the elements. A few specs on this harness, next ampridge 00:01:34 for the stop and turn light circuit is 3 amps per circuit.

For the tail light circuit is 6 amps total. Now this part includes everything shown here on the table that I've laid out, even has a nice set of detailed instructions to tell you how to install it but also gives you pictures to show you where the connection points are, helps out quite a bit. Basically what you'll do to install this, just go to the back of the vehicle and as I mentioned in the rear cargo area, you'll locate a connection point which it will show you in the instructions where it's located and you'll just unplug it and plug this in line to it. Once that's all plugged in the white wire right here with the eye lid on it need to connect that to a good clean ground. If there's one nearby you can use it. Need to make one, there's a grounding screw, that you can drill a hole and make a ground and then you have your power wire right here.

This has to run to your vehicles positive post of their battery so that has to run to the front of the vehicle, so they give you this extra length of wire. Take one of your butt connectors, put it on your power wire coming out of the converter and connect it to one end of your length of wire, run that wire all the way up toward the front of the vehicle, using these cable ties to take up any slack in that wiring. Once you get to the front with the other end, you don't want to connect this to the battery yet, you want to run it through this in line fuse holder. So take your other butt connector put it on there and connect it to one side of the in line fuse holder, just like that. Once that's all connected, you have your other side of the fuse holder, that's what will connect to the positive post of your battery, they includes this eye lid connect that you put on there, connect it to the positive post. Last thing you need to do is take your included 10am fuse, put it in the fuse holder just like that, put the cap on and you'll be all ready to go. Now one other thing I do want to mention to is this converter box, this black box here, it does need to be attached to a nice flat surface so it doesn't bounce around, so they do include some double sided tape to help with you that and some extra cable ties that you can also use to secure if you like. That should do it for the review on part number 56043, the Curt T-connector vehicle wiring harness with the 4-way flat trailer connector.

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 56043

Average Customer Rating:  4.0 out of 5 stars   (1 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.


Attaching the wire harness is a bigger deal than I expected. You will be required to run a hot wire from the trunk underneath the car to the engine compartment, attach an inline fuse and then hook it up to a connection that goes to the battery. The person on you tube that did it had the car up on a car lift to put in this wire. The clearance under my car is so low that there would be no way to install this harness without having a full car lift.If I had it to do over I wouldn't have bought this harness. Instead I would take it to a shop for installation, which I will have to end up doing anyway. Before buying this item I would watch the YouTube video first if I was you.


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

  • Can a Cadillac CTS-V Tow a Trailer
    I do have an option for you depending on what year your Cadillac CTS-V is but they do not offer a trailer hitch with a 2" receiver tube for this vehicle. As you mentioned, power is not an issue on the V model but other factors such as frame strength come into play when trailer manufacturers decide if they will offer a trailer hitch with a 2" receiver tube for the vehicle. Now, with that being said a 2" receiver tube is not required to tow a trailer but you will need to abide by the towing...
    view full answer...
  • Best Class I 1-1/4 Trailer Hitch for a 2007 Cadillac CTS
    We have hitches for your 2007 Cadillac CTS but there are no class II or above. The class rating system is based on weight and capacity of your vehicle and your cars towing capacity is only 1,000 lbs. The Curt Hitch item # C11307 is the best hitch for your car and will allow you to use your the full capacity available. If you need a wiring harness to control your trailer or accessories lighting functions you will need the Curt Wiring Harness with 4-Pole Flat Trailer Connector item # 56043. For...
    view full answer...

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

Info for this part was:

Employee Joe V
Test Fit:
Joe V
Employee Jeff D
Installed by:
Jeff D
Employee Alan C
Video by:
Alan C
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Isabelle B
Updated by:
Isabelle B

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