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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 # C56270
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Custom Fit Vehicle Wiring

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C56270 - 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. Call 800-298-1624 to order Curt custom fit vehicle wiring part number C56270 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.
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  • Reviews (14)
  • Q & A (10)
  • Photos
  • Why etrailer?

Curt Custom Fit Vehicle Wiring - C56270

  • 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 behind tail lights
    • 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: 7.5 amps per circuit
    • Tail lights: 7.5 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 and passenger's-side tail lights. You will have to remove the tail light assemblies to access this harness. 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.

56270 CURT T-Connector Vehicle Wiring Harness with 4 Pole Trailer Connector

Installation Details C56270 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C56270

Average Customer Rating:  4.8 out of 5 stars   (14 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.

- C56270
2019 Dodge Ram Pickup

For 2019 Ram Promaster City this wiring harness has everything that you need and has pretty good instructions. You need a fish wire to install this and I just used the black power line and was very gentle. lol. This is 4 stars and not 5 because the lengths of the wires that they give you are JUST long enough to do this. It would have made install easier if you had an extra 6-12 inches in some cases. Over all simple install but not "easy."

still working fine after one year with no issues and probably monthly use.
Joseph - 03/04/2021

- C56270

the Curt T-one vehicle wiring harness with 4 pole flat connector. The first one i received was defective through no fault of etrailer, and Allison did what was necessary to arrange the shipment of a replacement on a Sunday. This is not the easiest installation in the world. It's a little difficult to snake the wiring down to the tail lights, but very doable. I think however etrailer's video of this installation is somewhat misguided. Although I have the equipment to jack the van up and run the power wire underneath the van, it is ridiculous to do so. I found it much easier and faster to run the wire inside the van. This is done easily by removing the little black storage compartment above the left wheel well, (you need not even remove it all the way, just pull it out at the top,) run the wire behind it, then removing the left sliding door sill plate and zip tying the power wire to an existing harness underneath it, then removing the driver's door sill plate and zip tying the power wire to the existing harness there, then around and up under the dash, then poking a hole for the wire thru an unused feed-thru plastic plug on the firewall behind and below the battery. Very fast and easy. You should redo your video.

- C56270
Dodge Ram Pickup

I purchased this for use on a 2020 Ram Pro Master City Wagon. Although the installation is not difficult, it is rather involved. Reading the directions and also watching the online video atthetrailer.com was extremely helpful. You need to fish the wires down to each taillight. Are used a simple coat hanger for this. You also need to drop the headliner in order to transverse from one side to the other. All in all, it probably took me two hours from start to finish. Everything was plug and play and it works as expected.

- C56270

Very simple to install, plugged right in. 1 year after installing everything still works perfectly.

- C56270
2012 Ram ProMaster 2500

Dodge Promaster City, wiring harness for trailer hitch: The product works great. However, as noted on the website, this installation is tricky. As a matter of fact, it's a pain in the rear... If you have a work van version of the City, it would be a lot easier. I have a trimmed out 5 seater, though. The ceiling tray needs to be dropped and trim opened up on the rear drivers side in the storage area. I would recommend pulling your power from the 12 v cigarette lighter in this location, the fuse is plenty big for the lights and it's not that likely you'd be using both simultaneously. Installation instructions could be better, though. I agree with the assessment that this is an expert type install. If you've messed around with this stuff and can fish wires ( a coat hanger works well), shouldn't be that bad. An extra set of hands is really helpful, though.

We strongly recommend running the 12 volt power wire from this wiring harness directly to the vehicle battery. The 12 volt accessory circuit was not designed to support the additional load of a trailer wiring harness. A wiring harness must have its own dedicated circuit directly to the battery. We have seen many instances where customers have tapped into a 12 volt accessory circuit, like a car lighter socket, and the harness failed. We have also seen instances where the accessory circuit on the car failed in addition to the trailer wiring harness. Also, this will typically void warranties both with the wiring harness and on the vehicle. We understand that running the 12 volt power wire can be a more time consuming task, so we wrote a help article on tips for running this power wire, which may be found at this link. Be sure to avoid any moving components such as suspension or steering. You will also want to avoid any areas that get excessively hot. Again, thank you for your business and we look forward to doing business with you in the future.
-- Etrailer Expert Laura E - 09/19/2017

- C56270

No problems found at all. Works as exp ected.

- C56270
2019 Jeep Wrangler Unlimited

2nd order from them. Fast shipping and correct parts both times. Simple install, doesn’t effect vehicle lights at all.

- C56270
2018 Dodge Ram Pickup

good product. works as advertised. I used this on 2018 ram promaster city wagon. running the wire's wasn't easy but I did it , if I had to do it again I could do it faster than 5 hours knowing how to disassemble panels/headliner and route wire.

- C56270

Wow!!!! Fast shipping. Product was new and in mint condition. Will be ordering more

- C56270

After a year, lights still work perfectly. Easy to install. Great experience finding the item I needed and getting it fast.

- C56270
2015 Ram ProMaster City

Product fit perfectly per the installation instructions.

- C56270

Very Happy with this product still works well.

- C56270

Fast free shipping. Items arrived on time and are exactly as ordered.

- C56270
2017 Ram ProMaster City

perfect and video makes instillation a snap


Ask the Experts about this Curt Custom Fit Vehicle Wiring

  • Recommended Hitch Bike Rack For Two Hybrid Bikes
    You have the option of going with a hanging bike rack or a platform bike rack. I will give you a recommendation of each option. If you go with a hanging bike hitch rack I recommend the Yakima RidgeBack 2 Bike Rack - 1-1/4" and 2" Hitches, part # Y02457. What I like most about this rack is its installation into the hitch receiver. It uses a wedge for its anti-rattle hitch. So once you get the hitch pin holes lined up all you do is turn a knob to snug it to your hitch receiver. It has...
    view full answer...
  • What are Differences Between Curt and Tekonsha Harnesses?
    There are a couple of differences between the wiring harnesses for your 2016 Ram ProMaster. The biggest difference is the technology used. The Curt # C56270 uses what is called Surface-Mount Technology. Essentially what this does is almost eliminate the draw on tail light circuits. which traditionally draw the most amps. The Curt harness also has a maximum amperage of 7.5 amps per circuit on the stop and turn lights, while the Tekonsha # 118719 has a max amperage of 4.2 amps per circuit....
    view full answer...
  • Trailer Wiring Harness Recommendation for a 2015 Ram ProMaster City
    Both trailer wiring harnesses that you mentioned part numbers # C56270 and # 118719 have been confirmed as fits for your 2015 Ram Promaster City. Since we tend to have better luck with the Tow Ready brand I would recommend the # 118719. The price is also better for this harness we asll.
    view full answer...
  • Troubleshooting Wiring Harness That Stops Working Properly When Running Lights Are On
    The issue with your running lights causing the brake and turn signal to not work sounds like a common grounding problem that occurs often. Since the running lights remain on continuously they will draw more power than blinking turn signals or brake lights that are typically on for only a moment. This higher power draw is why those other functions can fail when you put on the vehicle headlights. The solution is usually very simple and easy. What you want to do on both the vehicle and...
    view full answer...
  • Park Sensor Warning Message on a 2018 Ram ProMaster City While Reversing with Trailer
    I took a look in the owner's manual for your 2018 Ram ProMaster City and did not see any way to manually disable the ParkSense. More often than not, you can disable the parking sensors in the information panel on your cluster but I was not able to confirm this for your Ram ProMaster City. The sensors are supposed to automatically deactivate when the transmission is placed in reverse with a trailer connected but this is for Mopar wiring harnesses only. You can try turning the key ignition...
    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...
  • Can the Trailer Connector for the Curt Wiring Harness On a 2018 Ram ProMaster Be Routed Outside
    The Curt T-Connector Vehicle Wiring Harness part # C56270 which is a fit for a 2018 Ram ProMaster City can be installed so that the trailer connector is stored outside of the vehicle. In order to do so you will simply need to route the trailer connector through a grommet in the floor outside to the rear bumper. I don't have exact instructions on this but essentially you just need to peel up the carpet/panels near the rear bay access doors and then look for a grommet you can use to route...
    view full answer...
  • Will the Curt T-Connector or T-One Disable Park Sensor Warning on a 2016 Ram ProMaster City
    The only trailer wiring harness I am aware of that disables the park sensor warning message on a Ram ProMaster City is the Mopar Trailer Tow Wiring Harness. The T-One Vehicle Wiring Harness part # 118719 and the Curt T-Connector Vehicle Wiring Harness part # C56270 will not disable the park sensor warning message so if you use either of these you may get an in-dash error message while in reverse with a trailer attached. This will not have an effect on anything but it can be rather annoying....
    view full answer...
  • Brake Controller Install on 2015 Ram Pro Master City
    You will need to start with a 4-way (if you do not have one). For that you would want the # C56270. From there you would need to convert the 4-way to a 7-way so that you can install the brake controller. For that you will want the Brake Controller Install Kit and 7-Way Adapter part # ETBC7. I attached installation instructions and an install video for this product as well. For a brake controller I would recommend the Prodigy P2 Brake Controller part # 90885. This is our best selling...
    view full answer...
  • Ground Clearance of Curt Trailer Hitch Receiver on 2017 Ram ProMaster City
    When we installed the Curt Trailer Hitch Receiver # C13215 on a 2018 Ram ProMaster City, we measured it to have 9" of clearance to the ground. This measurement may differ with your 2017 Ram ProMaster City as depending on cargo loading, that will vary the suspension. It will hang approximately 3-4" to the base of the hitch below your factory bumper cover. If you are towing with your ProMaster you will need the Curt Wiring Harness # C56270. This will give you your lighting circuit...
    view full answer...

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Info for this part was:

Employee Lindsey S
Written by:
Lindsey S
Employee Jameson C
Expert Research:
Jameson C
Employee Adam R
Expert Research:
Adam R
Employee Joshua S
Video by:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Cole B
Installed by:
Cole B
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Isabelle B
Updated by:
Isabelle B
Employee Ryan G
Test Fit:
Ryan G

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