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  1. Custom Fit Vehicle Wiring
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  4. CURT
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 # C56209
Our Price: $80.64
You Save: 39%
Custom Fit Vehicle Wiring

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The best technical support and full custom fit vehicle wiring installation instructions. Great price custom fit vehicle wiring and expert service. Ram , 2022 custom fit vehicle wiring by CURT are available from For expert service call 1-800-940-8924 to order your Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part number C56209, or order online at
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  • Reviews (80)
  • Q & A (0)
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  • Why etrailer?

CURT Custom Fit Vehicle Wiring - C56209

  • 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
  • Limited 1-year warranty


  • Maximum amperage:
    • Stop/turn lights: 4.2 amps per circuit
    • Tail lights: 5 amps per circuit
  • Limited 1-year warranty


This custom-fit T-connector plugs into your vehicle's wiring harness, which is located in your rear cargo area, behind the driver's-side and passenger's-side tail lights. You will have to remove the interior plastic covers to access these connection points. Once you've plugged in the T-connector, run the hot lead to your car battery under the rear floor panel on the driver's side. 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.

56209 CURT T-Connector - Surface Mount Technology - 4 Wire

Installation Details C56209 Installation instructions

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C56209

Average Customer Rating:  4.8 out of 5 stars   (80 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.


Install isn’t too bad if you haven’t outfitted the van too much but it can be inconsistent at times the driver turn signals come on at random. I later found out it’s due to an electrical issue somewhere in the line. So I unplug it when I don’t use it; but it functions as claimed when i use it. Just not super stoked on it’s set up and function

2016 Ram ProMaster 1500

It doesn't work! The installation was quite easy, there is no way to install it incorrectly. However, when I plugged into the trailer, the trailer lights come on, the keys of the 2016 Ram Promaster van weren't even in the ignition and the lights weren't turned on. When I turned on the key the lights still remained on with the van lights turned on or off, turn signals and brakes don't work at all. The lights and wiring harness on the trailer are brand new and they worked perfectly when connected to two of our other trucks. There is definitely something wrong with this wiring harness.

I recommend trouble shooting with the wiring harness starting with checking the ground wire. You will want to make that it is to bare metal and has a clean connection. We do have a great FAQ that can help that I have linked below.
-- Etrailer Expert Jenny N - 03/22/2022


This was my second CURT harness that failed me. I have a Tekonsha harness now which I've had for 2 months now. So far so good.


Harness was exactly what I needed. Instructions were good, and installation went without any problems. And, it worked great.


No complaints.


I'm very pleased with this wiring kit... fit perfectly. There were a few awkward spots to fish wires/plugs through, but not too bad. The installation video was extremely helpful, although I did a couple things slightly differently. The van in the video had a finished interior. A plain cargo van has plenty of openings in the framework to run wires through, so I ran my (right taillight) wire through the frame over the doors, not tucking it in the weatherstrip. Up front, I opted to follow Curt's printed instructions, removing the plastic step-well. There are a couple wiring clips and a raceway behind there that give good protection to the main power wire. I'm sure the video's under-the-seat technique would be quicker, though. I don't expect to pull a trailer a lot, so for now at least, I'll store the plug clean and dry inside, below the taillight, and just pull it out when needed.

Still working just fine, no glitches.
Dover D - 08/14/2017


Easy Peasy, works as it should


Products and prices are excellent


I received the hitch and wiring harness very quickly!
The video on line was very helpful for installation.
Everything went together just like it was planned.
Very pleased! Thank You


Exactly what we needed for our hitch


Installed and worked as should.

Dodge Ram Pickup

biggest problem i had with installation was dodging rain storms hitch an wiring fit perfect wish ram would have made bolt on bumper a little longer Karen C did a great job. shipped on a Tues. afternoon received on Fri.130pm.

just fine no problems
jim m - 05/29/2015

2019 Ram ProMaster 2500

The item I ordered part number c56209. Was so easy to install it was basically plug and play . Now my promaster van is ready to pull a trailer . Thanks guys

2020 Ram ProMaster 1500

Nice. Be sure to watch the retailer install video and NOT the other one on YouTube. The control box goes inside the van, not underneath the bumper.

2014 Ram ProMaster 2500

Trailer wiring harness for a 2014 Dodge Promaster van. YOur instructions showed more than the dealer knew. They claimed there were no wiring plugs where they were supposed to be and you showed me there were! Installation took one hour. Really pleased with the handling of my wo orders with you folks. I pass your address to many of my friends. I did have a bit of a problem figuring out what to do with the black wire on the module.

Dodge Ram Pickup

Very helpful instructions. Step by step. No questions. Installed new wiring kit in 1 hour on my brand new Ram van.


Well engineered hitch! Very straightforward installation and excellent directions. I'm a beat up retired nuc plant mechanic. And it took less than an hour to install. Excellent service from etrailer too. Shipped out very quickly and it was very well packed as well. All in all, you folks are an outstanding trailer resource! Thanks! This coming week I'll install the wiring kit.

2019 Dodge Ram Pickup

Just installed this wiring harness on My RAM Promaster 1500 cargo van. Watched the videos on e-trailer on how to do it. No issues. Well made product. I would but it again.


No problems with installation


Installation was simple. Limited tools or knowledge required. Works as described.

2015 Ram ProMaster 2500

Always great products and simple installation. I have purchased 3 hitches from etrailer over the years and always 5 stars. I haven't installed the wiring kit yet but the video installation they provide is spot on. Thank you.

Dodge Ram Pickup

Class III hitch was easy to install and fit perfectly on my Ram van, no fuss, easy to follow instructions

2017 Ram ProMaster 1500

I watched a video installation of the wiring. I was able to wire it perfectly.... The wiring for trailer worked amazing after I tested it all out!!!

Very happy with Product


Got the hitch now harness kit great product recommend it to all the pro master owners easy install


Save yourself some headaches and run the power wire under the vehicle like the installation video shows. Its much easier than trying to fish it through the inside. Great video by the way. Thanks.

Show More Reviews

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

  • Trailer Wiring Recommendation for 2017 Ram ProMaster 2500
    The best trailer wiring option we have for your 2017 Ram ProMaster 2500 is the part # C56209. It's custom fit so it installs easily and also has a very reliable converter box as well. I attached an install video for this on a similar ProMaster for you to check out as well.
    view full answer...
  • Troubleshooting Curt # C56209 that Blows Fuse Immediately
    Does the fuse blow with the trailer disconnected or only with the trailer connected? You have a really bad short somewhere but it's a matter of narrowing down where it is to fix it. If the fuse blows with no trailer connected you need to most likely go over the power wire for the wiring harness part # C56209 as it sounds like there is a short there. This is most likely the case as this is the only wire that should see power all the time to immediately blow a fuse.
    view full answer...
  • Trailer Wiring Recommendation for a 2015 Ram ProMaster 2500
    You are correct. The Curt wiring harness part # C56209 that you referenced is the correct trailer wiring harness for your 2015 Ram ProMaster 2500 with a 159 inch wheel base. We confirmed this fit with Curt.
    view full answer...
  • Curt Trailer Wiring Harness that Fits 2022 Ram ProMaster 1500
    We do have Curt trailer wiring that fits your 2022 Ram Promaster with the part # C56209 which installs easily by plugging inline with the vehicle taillights.
    view full answer...
  • Troubleshooting Trailer Lights Not Working with Curt T-Connector Harness Installed on Ram ProMaster
    Since all of the trailer lights worked fine when using a different vehicle, it does seem like you have narrowed down the issue to the wiring on your 2018 Ram ProMaster 1500. To further verify this I do still recommend testing the 4-Way connector on the vehicle with a circuit tester like # PTW2993. Test the pins on the connector while you have a buddy activate the signals in the van. If you aren't getting power to all the pins then I recommend testing the wires both before the converter...
    view full answer...
  • Trailer Wiring Harness For 2015 Ram ProMaster 2500
    If the 2015 Ram ProMaster does not have the factory tow package, the Curt T-connector # C56209 will work for you. On page 16 of the installation instructions for the SMI Stay-IN-Play system, part # SM99251, the following note states : This installation assumes your tow wiring is based on a standard 4-wire connection from the motor home. If you have a separate wire for the brake signal from the motor home (amber turns on the towed and coach), find the wire that receives 12v (+) when the...
    view full answer...
  • How To Add a 7-Way Trailer Connector to a 2016 Ram ProMaster 2500
    If you do not currently have a trailer wiring harness on your 2016 Ram ProMaster 2500 then we first need to start with a 4-way for which I recommend the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # C56209 because it is plug and play, also cost effective. Then, in order to convert this 4-way into a 7-way we can use the Adapter 4-Pole to 7-Pole and 4-Pole part # 37185. The only wires you need to connect with this adapter save for the 4-way is the white...
    view full answer...
  • How to Use Quick Splice Connectors or 3M Scotchloks and Wiring Harness for 2014 Dodge ProMaster 3500
    To use the quick splice connectors, you will put the wire you want to splice into on the inside track of the connector. Then put the wire from the wiring harness # C56190 in the track next to it. Close the plastic clip and use some pliers to squeeze the connector to make the splice. I have included a link to a video that shows our installer using the connectors. Go to about the 56 second mark to see it in action. Be sure to test the wires first with a circuit tester such as # PTW2993....
    view full answer...
  • Trailer Lights Stay On When 2016 Ram Promaster 2500 Ignition Is Off
    The Curt Wiring Harness part # C56270 is designed to fit 2015-2019 Ram ProMaster City. Since you have a 2016 Ram ProMaster 2500 you want Curt T-connector part # C56209. I was not able to find any relays that are related to the function of trailer lights so I do not believe that is the issue here. Usually if a relay or fuse is missing under the hood or in the power distribution box then you would not have power to the trailer lights at all. If you have the correct T-connector and your...
    view full answer...
  • Easy To Install Brake Controller for 2017 Ram Promaster
    Hardwiring a brake controller to your 2017 Ram ProMaster 2500 is going to be challenging especially since you don't have a 4-way at this time either. I have a much easier solution though that you will really like. If you instead go with the Curt Echo Mobile brake controller # C51180 you'll only to run one single wire after installing the 4-way which makes life much easier. Basically this plugs into a 7-way with an active 12 volt power circuit and gives you a proportional brake controller...
    view full answer...
  • Can You Test the Curt T-Connector Vehicle Wiring Harness With a Volt Meter
    Yes, you can use a volt meter to test a trailer wiring harness like the Curt T-Connector Vehicle Wiring Harness. You'd simply be looking for around 12 volts on the circuit you have activated. The other ways we recommend testing are with a more basic test light like part # PTW2993 or plug in tester like part # F4CT. The harness don't read resistance on the circuit or anything so as long as you have power to the module box and the signal is activated in the vehicle then you will see power...
    view full answer...
  • How Does Aries Automotive Seat Cover Stay In Place on a 2018 Ram ProMaster 2500
    On seat cover # AA3142B the back side has a non-skid type of material that will grip the seat portion and the seat back to help prevent it from coming out of position. It is still possible, if conditions are right, for it to come out of position. I have included a link to our returns policy for you. Curt trailer hitch # C13295 is a fit for your 2018 Ram ProMaster 2500. I have included a link to a video showing an example installation on a similar van for you. Curt wiring harness # C56209...
    view full answer...
  • Troubleshooting No Running Lights on Trailer Hooked Up to 2019 Ram Promaster 2500 With 4-pole Flat
    First, it is a good idea to check the ground coming from the wiring harness. A lot of times if one function is working and the other is intermittently working or not working at all the ground is bad. Make sure the ground is grounded to a clean bare metal surface of the vehicle's frame. You also want to make sure the plugs are seated properly and the pins are not bent on the vehicle harness and the trailer connector harness. If your connections are okay, you want to test the brown wire...
    view full answer...
  • How to Add 7-Way & 4-Way to 2022 Ram ProMaster 3500 Without Factory Tow Package
    We can definitely accomplish your goal, which is to have a wiring connector on your 2022 Ram ProMaster 3500 with both a 7-way and a 4-way. While you cannot use the # C56209 without connecting it, the 7-way adapter you'll use actually has a plug on the side that allows a 4-way connection, as you can see in the photo I added. Since your '22 ProMaster does not have the tow package, the first thing you'll need to do is install a 4-way. And while the Curt T-Connector # C56209 will fit, I highly...
    view full answer...
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