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  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 # C56181
Our Price: $77.72
You Save: 37%
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. 1-800-940-8924 to order CURT custom fit vehicle wiring part number C56181 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 (66)
  • Q & A (0)
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  • Why etrailer?

CURT Custom Fit Vehicle Wiring - C56181

  • 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 powered tail light converter that 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

Note: This wiring cannot be installed if your vehicle has a rear air conditioning unit.


This custom-fit T-connector plugs into your vehicle's wiring harness, which is located behind your tail lights. To access these connection points, you will have to remove your rear scuff panel. 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 in your rear 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.

56181 Curt T-Connector - Surface Mount Technology - 4 Wire

Installation Details C56181 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C56181

Average Customer Rating:  4.8 out of 5 stars   (66 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.


I bought this wiring harness after watching the installation video on the Etrailer website. I installed this in my driveway with the use of my floor jack. It took about an hour for me to install it. It was easy to install and it worked without flaw the first time. Great product! Great company! Thanks!


It was easy to install and works great. Haven't had any problems with it.

by: 04/21/2022

We did not put it on but it was the right part and our local auto service had no issues! No issues with lights or harness as of yet! Thanks so much!

2013 Lincoln LS

Easy install 2013 LS FWD. I had no issues after following the video. The only thing they did not show was having to unbolt part of the battery box heat shield to gain access to the battery vent.
I went the extra mile by installing 1/4 harness wrap on the green wire through the bumper rail and the positive all the way to the battery box. There are some sharp edges under the body that could cause a short over time with no protection. I also purchased the 4 plug tester. All is good.

Product failed after 4 months. Left rear turn signal would stay on solid even with the car off and keys out. I did a full wire harness wrap during installation so no shorts. Took forever to get a replacement.
Brian W - 09/17/2019

Saturn Relay

I ended up cutting thru to tail lights with a hole saw to get the connectors thru into the tail light recesses they fill the hole with shoe goo to seal. It really worked better than it sounds. My LTZ has rear heat/AC on on one side and power hatch lift on the other so the connectors for hitch wiring were not accessable. i did connect into the rear power plug for 12V power for the relay so I didnt have to run all the way to the battery.

A powered taillight converter should draw its power from a direct connection to the vehicle battery, but will gain its switching information via its connection to the vehicles taillight harness or tow package connector. Years ago, taillight circuits in vehicles used higher gauge wire and had enough capacity to handle the draw of the vehicle taillights as well as those of a trailer. Now that the price of copper has gone through the roof and vehicle manufacturers try to save all the weight and expense they can, the taillight circuits use smaller gauge wire that can handle the load from the vehicle taillights but not much else. Drawing the power directly from the battery also serves to isolate the tow vehicles sensitive electronics from any short circuits that might occur in the trailer wiring. Connecting the converters power feed anywhere other than the battery or where the converters manufacturer recommends can leave your vehicles electrical system exposed to possible damage.
-- Etrailer Expert Mike L - 03/06/2019
The trailer electrical has worked great every time I have used it.
Ronald A - 03/07/2020

2017 Chevrolet Traverse

I bought a trailer hitch for my Chevy Traverse and it went on easily and works well, however the trailer light package burned out in November 2017. It blew fuses and I could smell hot plastic. I did not find any shorts in the wires, it may have been the plastic "black box" part of the wiring harness. I have since replaced it with the type of harness that plugs into the plug by the left rear fender. I also purchased that from etrailer. Hope it works.

The majority of the time when a converter box shorts out, the cause is a short circuit somewhere in the wiring on the trailer. Begin by checking the trailer connector, look for damage or corrosion. Trace each circuit rearward looking for pinched or broken wires. Check that all connections are secure and protected from the weather. Carefully examine the wire insulation, look for worn or cracked spots that would allow the copper wire to contact the trailer frame or other metal and cause a short. Youll want to located and repair the short before replacing the taillight converter, or youll continue to blow out converter boxes.
-- Etrailer Expert Mike L - 01/05/2018


It was delivered on time and care.

2015 Chevrolet Traverse

I bought products:C56181,TM75127, D13035, D/3503, 39523, PS49903, ETBC7, from E Trailer, and installed them on my wife's 2015 Chevy Traverse. Over all the products were pretty easy to install, but it still took a while to do it right. When installing the Brake controller, and connecting to the brake petal switch connect to the white wire in plug taped back on the left side under drivers side dash, and do so on the plug prong, with a female spade crimp terminal, not the inline crimp connector provided, they aren't very reliable I my experiences. Also soder all your but joints and heat shrink, or tape, I've had too many problems with crimp terminals corroding. On the Transmission cooler get some very light gauge 1 1/2 x3" angle iron and mount your cooler to it on the 3" side suspending down from at least 3 front grill torx headed screw ran through the 1 1/2 side of angle, I didn't like the idea of shoving the chess plastic mounting kit through my radiator, plus it eliminates the need of removing electric fans and this way you only hafta take top screws out of front grill and slide cooler and bracket down through. Thanks E trailer for compiling all videos these were very helpful?

2015 Chevrolet Traverse

Easy install, however my first wire harness the control box stopped working after 2 months of use. Just installed my new harness. too early to tell if this will fail as well.

The most common reason a converter box fails is a short circuit in the trailer wiring. Youll want to closely examine the wiring on your trailer, beginning at the trailer connector and working backwards tracing each circuit until you reach each lamp. Look for loose connections or pinched wires. Closely examine the plastic insulation on the wire, looking for cracked or worn insulation that would allow the copper wire to short out on the trailer frame. If there is a short somewhere in the trailer wiring, youll continue to fry converter boxes until the short is located and repaired. Ill link you to a help article that contains lots of good information about troubleshooting trailer wiring systems.
-- Etrailer Expert Mike L - 06/01/2018

2014 Chevrolet Traverse

I started with a "this will work kit" from my local parts store...turns out it was only for a Traverse that comes with towing package, which I do not have...out $40. Next I stumble across this harness from etrailer... exactly what I needed! Quick shipping and super great instructions with photos specific to install to my traverse...all the way down to which screws to turn. Plugs into the taillights plus a hot wire from the battery.



2015 Chevrolet Traverse

The wiring harness itself it really great. My vehicle did not have a factory trailer wiring harness. This one did take about 4 hours to install. I have no lift, so I used my jack to lift the right rear off the ground to crawl under the car to run the power wire to the battery. My vehicle also has the rear AC and ventilation controls which makes the right rear side too difficult to access the wiring grommet, so I routed all the wires out the left side and spliced the right directional wire (green) going to the right side to gain the extra length I needed. Beyond that I would suggest using some plastic spiral insulation around the wires to protect them against sharp edges of the metal body.

2015 Chevrolet Traverse

As with all tasks around my house, I have to do things myself. Installing this 13424 receiver hitch on a 2015 Chevy Traverse LTZ was no exception. The biggest challenge was loosening the dual muffler rubber hangers, 2 per side. The other issue was how to hold this 25-50lb receiver hitch with one hand while screwing in the bolts. By creating a third hand, the whole process took me about an hour. Fit beautifully, well made and solid. Fun part - the carriage bolt fish wires.
Just need to have the wiring harness installed by a professional. Did that myself on an old vehicle and some years later sent my dashboard lights into a tizzy because the device got wet and shorted.

I would buy a CURT product again.

2017 Chevrolet Traverse

Yes we received your product but haven't installed it yet.
The only thing I couldn't figure out is why it took a week to ship an in stock item.


The wiring harness made it simple to hook up. Hitch also worked perfectly. I'm glad I went with e-trailer. Definitely recommend them.


The trailer hitch was fairly easy for my husband to install on my Chevy Treverse and has served its purpose well. We have a 6ft trailer we hook to the back for hauling firewood and items for projects. We have been very happy with the quality, prices and delivery time of all the products we have ordered from etrailer.


Great product, installation was a breeze. I changed a few things like running the green passenger side wire through the rear bumper tube and instead of running a wire all the way to the battery I was able to splice into the power going to the rear power outlet. This outlet has 20 amp fuse feeding it under the hood so the 10 amps needed for the trailer wiring should never be a problem. Use only a few tools to install(knife, wire stripper/cutter, small screw driver, and a nut driver). Very high quality kit with online videos to walk you through the process. Took me an hour to install on my garage floor.

2014 Chevrolet Traverse

I bought the draw tite trailer hitch and the t connector 4 way flat wiring harness for our 2014 traverse. It was very simple and easy to install. No issues as of now and I will be using it to tow our camper in a few days.


The curt wiring harness lasted one year then the left side shorted out and blew the fuse for my left running lights on the car.had to buy another one.i hope it lasts longer or i will have to go another way.

2015 Chevrolet Traverse

Seeing as I leaped (and ordered) before I looked, my new Traverse was equipped with a hitch. etrailer's customer service rep Lisa guided me through the process of making a return. She was so very helpful. I give etrailer a 5 star rating, because this is my third order from them and they always supply the best products, at best prices, and now I applaud there customer service. I will return again when ever a need arises. They are the first I turn to.


Easy plug and play harness! Recommend using more weather proof connectors though. Great installation video to ease installation! When installing this will need mechanics wire to help "fish" wiring through rear bumper support as described in video.

2013 Chevrolet Traverse

This hitch system was so spot on to install easily onto my 2013 Chevy Traverse. I did most of it by myself. The holes all lined up perfectly. The only worry I have is with the very basic brake wire that runs under the chassis to the front end. We get a lot of extreme weather elements in Minnesota and chemical spray from the roads. It maybe could have been offered with a protective sleeve.

2016 Chevrolet Traverse

hitch fit perfectly, the wiring kit said it could not be installed on traverse with rear air, not true, it installed great on my 2016 without a hitch and works great, just have to be creative on routing the wires...

2014 Chevrolet Traverse

The functionality of this unit is great! The installation video and instructions are lacking. Several direction steps were not hard they simply were impossible. If the part about most vehicles have the trailer wiring tucked up the side would have been great to know before we purchased. Also a description of what to look for would have been a help also.

2013 Chevrolet Traverse

Everything I needed was provided in the wiring kit. Installation instructions were easy to follow. The only thing I found in error was the location of the battery which was shown to be under the hood, it is located in the floor behind the passenger seat.

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