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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 # C56039
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Custom Fit Vehicle Wiring

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Curt Trailer Hitch Wiring - C56039
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Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. Connector plugs directly into existing wiring - no cutting, splicing or tapping required. Converter is made using SMT to ensure superior performance. Call 800-298-8924 to order Curt custom fit vehicle wiring part number C56039 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 (16)
  • Q & A (3)
  • Videos (1)
  • Photos
  • Why etrailer?

Curt Custom Fit Vehicle Wiring - C56039

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

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. Connector plugs directly into existing wiring - no cutting, splicing or tapping required. Converter 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 - no cutting or splicing of wires
    • Locate connection point in rear cargo area
    • Plug in connector
  • Includes a tail light converter to ensure that your vehicle's wiring matches that of your trailer
  • 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 installation is complete, the 4-way connector will be stowed beneath your vehicle, near the trailer hitch. A mounting bracket (sold separately) is recommended to keep the connector secure.

It is recommended that you use a small amount of grease on all electrical connections - the plug on your automobile and the 4-pole connector itself - to help prevent corrosion.

Tail Light Converter with Surface-Mount Technology

A tail light converter is built into this T-connector. 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.

56039 CURT T-Connector - Surface Mount Technology - 4 Wire

Installation Details C56039 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 T-Connector Vehicle Wiring Harness Installation - 2011 Mitsubishi Endeavor

Today in our 2011 Mitsubishi Endeavor, we're gonna be installing Curt's T-connector vehicle wiring harness with four pole flat trailer connector. This four pole vehicle wiring harness is gonna provide you with all the necessary lighting you need for your trailer. This includes your left turn signal, right turn signal, tail lamps and brake lamps, so you'll be D.O.T compliant in all states.What's nice about this is that it has its own control unit. The control box that comes with it will isolate your trailer wiring from your vehicle wiring. That way if you have any faults on your wiring it won't affect the wiring on your vehicle.On the end here you'll also receive a dust cap so when you're not using your connector you can place it on. This will keep out any dirt and debris, insuring a long lasting connection.

Additionally, you can use this to secure it to your safety chain loop if you don't have a bracket for your four pole connector.We'll begin our installation at the back of the vehicle with our rear lift gate open. You're going to need to take your spare tire cover off, we're going to set it aside. Next we're going to need to remove the panel on the driver side next to our spare tire cover. There are two anchors that we're going to need to remove by flipping them up and removing the bolts underneath with a ten millimeter socket, and set it aside.You'll find the connector for your factory harness here on your vehicle. We're going to pop it out of the little compartment there that it's in and we're going to plug our new harness right into that one.

We can now install our ground wire, that's the white wire with the ring terminal on the end here. Take the self tapping screw that comes in your kit, we're gonna place it through there. We're just gonna run it into the metal right down here next to it. We're gonna use a quarter inch socket to do that.Next we'll need to remove our spare tire, so unscrew your hold down. We're just gonna flip the spare tire up out of the way, revealing the grommets that are located beneath it.

We'll route our wiring over towards the grommets and we're gonna go ahead and lift up on one of the grommets here. We're gonna do the closest one to our wiring. We're going to route our wire down towards our hitch.We'll now take our grommet . We're gonna go ahead and put a slit in it for our wiring, so I'm just gonna use a razor knife. You could also use a pair of tin snips or scissors, which ever you've got.

I'm gonna cut that, this way our wiring can be pushed through the grommet. We'll use the silicone that comes with our wiring to seal it back up. We're just going to take that slit we made and fill it all back in with the black silicone.We can now reinstall our spare tire. We'll now take the adhesive backing that comes in our kit, we're going to place it on our module here. We'll then take the other end of our adhesive backing, peel that off and we're just gonna take our module and we're just gonna stick it right here. All that's left is to insert your fuse into your harness. Now we can reinstall all of our paneling. You can now take your wiring and zip tie it to your hitch. We thought ahead and installed a bracket to keep it nice and secure. This bracket you can pick up here at etrailer.com.So now you can plug it in to your trailer or a tester. We're going to be using a tester here. You can pick one up just like this at etrailer.com and verify everything's working properly. You'll want to make sure that you have your left turn signal, right turn signal, tail lamps, and brake lamps. With everything working properly, ready to hit the road.That completes our installation of Curt's T-connector vehicle wiring harness with four pole flat trailer connector on our 2011 Mitsubishi Endeavor.

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C56039

Average Customer Rating:  5.0 out of 5 stars   (16 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. Connector plugs directly into existing wiring - no cutting, splicing or tapping required. Converter is made using SMT to ensure superior performance.

- C56039

worked fine 744521

- C56039
2006 Mitsubishi Endeavor

Excellent wiring harness and easy insta llation. 646705

- C56039
2004 Mitsubishi Endeavor

If it was any easier to install this, I could have had my 4 year old granddaughter put it in. Shipping was 2 days. So fast. Etrailer personnel are the most courteous, helpful people I have seen in a long time. I am a customer for life.Thank you very much. Art Deets Missouri 617543

- C56039
2005 Mitsubishi Endeavor

easiest install I've ever done. packaging was great and the description of the item was great. i got email updates throughout the whole shipping and order process. 542749

- C56039

Works great! 475679

- C56039

Very easy install. Still working after one year. 470546

- C56039

etrailer made it so easy to install the hitch and wiring harness for my Mitsubishi. I would have probably paid someone else to install these products for me, but the videos and installation instructions provided were made specifically for my vehicle; which made installation a cinch! It's a professional looking install with quality products, and ordering and shipping were a breeze! I'm very satisfied. 412099

The wiring harness was easy to find, easy to buy, and easy to install with the video. One year later, still works like it was new. No complaints. Ill buy from etrailer again!
Rick F - 07/31/2018


- C56039
Chevrolet Silverado 2500

Shipped quickly. Everything fit like a glove... not OJ's... Wiring was quick and easy. Towed a 14ft trailer loaded with a 2500 lb swing set 600 miles. Nothing loosened. Held up great. Good experience. 401001

- C56039
2011 Mitsubishi Endeavor

Overall everything was excellent! Easy to find the product I needed, it was delivered very quickly and the installation instructions were very easy to understand. The installation instructions had pictures! Excellent! 394160

- C56039
2006 Mitsubishi Endeavor

Easy install for Mitsubishi. Thanks! 389150

- C56039

This assembly installed exactly as advertised. I was a bit skeptical at first after spending at least an hour on previous wire harness installations from other vendors. I will definitely order from etrailer again. 209641

- C56039

From beginning to end of my order I was completely satisfied. The customer service that I received was awesome. It's so refreshing to speak with someone who has the knowledge required to do a job well. The rep I spoke to was more than helpful. Knowledgeable and extremely patient in answering all my questions and the call was then followed up by a personal email. The product I received was exactly as described and yes it was the right one the first time.... easy to install and works perfectly. Thank you etrailer.com I will definitely be using your services again 96310

- C56039
2004 Mitsubishi Endeavor

Very easy to install. I love how easy it was. Would buy again. 94998

- C56039
2004 Mitsubishi Endeavor

The product was top notch and customer service was even better. It took less than ten minutes to install and test the harness assembly on my 2004 Mitsubishi Endeavor! 89368

- C56039
2011 Mitsubishi Endeavor

Very satisfied. I added 1 extra small bolt and washer not included in package. Maybe wasn't necessary but I wanted it to be grounded well. 79916

- C56039
2004 Mitsubishi Endeavor

just what I wanted-it plugged right in and worked great 69460


Ask the Experts about this Curt Custom Fit Vehicle Wiring

  • Hitch and Wiring Install Instructions for a 2011 Mitsubishi Endeavor
    The recommended trailer wiring harness for your 2011 Mitsubishi Endeavor is the Curt Harness part # C56039. We have not had the chance to install this harness on an Endeavor like yours so I do not have a video I can show you, but I did attach a set of the installation instructions that details how this harness installs. For a hitch for your vehicle you would want the Curt Hitch part # 13113. We do have an install video for this product that I attached for you to check out. For ball...
    view full answer...
  • Where Does the White Wire of the Curt Wiring Harness # C56039 Go on a 2011 Mitsubishi Endeavor
    The white wire you referenced actually needs to get run to a clean metal surface on the body of your 2011 Mitsubishi Endeavor with the included self tapping bolt through the ring terminal. This grounds the converter and allows it to function properly.
    view full answer...
  • Trailer Hitch Recommendation for 2007 Mitsubishi Endeavor
    For your 2007 Mitsubishi Endeavor the Draw Tite hitch part # 75519 and the Curt hitch part # 13113 are both a confirmed fit. If it were me I would go with the Curt hitch part # 13113 which we have an install video for that I attached which will walk you through the install process. If you wanted to do some towing you might be interested in etrailer ball mount kit # 989900. It comes with 2 ball mounts; one with a 3/4 inch rise or 2 inch drop and one with a 2-3/4 inch rise or 4 inch...
    view full answer...

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Info for this part was:

Edited by:
Leah B
Written by:
Lindsey S
Expert Research:
Jameson C
Video Edited:
Dustin K
Video by:
Chris R
Updated by:
Sarah W
Updated by:
Kristina F
Updated by:
Isabelle B
Test Fit:
David F

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