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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 # C56148
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Custom Fit Vehicle Wiring

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Custom Fit Vehicle Wiring C56148 - 4 Flat - Curt
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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 C56148 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 (13)
  • Q & A (4)
  • Videos (1)
  • Photos
  • Why etrailer?

Curt Custom Fit Vehicle Wiring - C56148

  • 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 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.

56148 CURT T-Connector Vehicle Wiring Harness with 4 Pole Trailer Connector

Installation Details C56148 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 Review of Curt Custom Fit Vehicle Wiring - 4-Pole Trailer Hitch Wiring - C56148

Ellen: Hey everybody, I'm Ellen here at etrailer.com. We're going to be taking a quick look at the Curt T-Connector Vehicle Wiring Harness. This is a wiring harness that allows you to have a four-pole wiring plug at the back of your vehicle so that you could work with any kind of trailer that uses the same, or any other accessories that might also use a four-pole flat.So it comes with everything you need to get this installed minus a few tools to undo any kind of panels, or get the connection to your battery. So let's take a closer look, talk about some of the specs in a little, go over a little bit how you're going to get this installed. The nice thing about the wiring again, is that it pretty much comes as you see it. And there's no real changes that you'll have to make to your vehicle's electrical system.

It's going to work with the plugs that you have already. So just plugs in line with the wiring behind your taillight housing. This is going to be for the driver's side, the green and red will be for your passenger side. So you just unplug that connection to the back of the taillight, plug these guys in right in line and should match up directly with what you already have. So again, you don't have to cut into any kind of existing wiring there.So in addition to those two connections, we'll also have a power wire.

This goes up to your battery or maybe a fuse box, but most likely it's going to go up to your battery on this vehicle. This kit is a custom fit for the 2012 through the current model year Nissan NV. And that's going to be for the 1500, the 2500 and the 3500.Power connection goes up to your positive side of your battery. Get some bulk wire to make that connection, as well as a couple of buck connectors, a ring terminal, and a fuse holder. That will need to go in between that bulk wire and the positive side of your battery to make sure that there's no issues with that.

Comes with a 10 amp fuse to go into the fuse holder. And then our last connection will be our ground. Comes with a screw to make that connection, or you can always find a factory stud somewhere nearby to the box.This box is going to be kind of the nerve center of the wiring. It's going to be the thing that converts the signal from our electrical out to the four pole on the back of your NV. So you want to mount this in a nice, kind of tucked out of the way area.

You do get some zip ties to make that connection, or to get everything cinched off. You always want to use zip ties to keep your wire bundled up so there's nothing hanging down, especially if you're going to be running that power wire underneath the vehicle. You want to be able to anchor that wire off to a nice secure spot. So it's not going to get tangled up or anything like that, and always avoid anything that's going to be moving like your suspension or your wheels, and also anything that's going to be hot, like your exhaust.You do also get a little piece of foam tape double-sided foam tape. So you can use that to stick onto your box as well. Something I've seen, sometimes this can get a little bit strained, especially if you're going over any kind of rough terrain. So you can actually use a zip tie around this tape, and kind of make sure that it stays in place, because it usually will stick better to metal than it does to this box. And that's just kind of a double insurance on it as far as keeping that secure.On our four pole flat, we do have a little dust cover to make sure that there's no water or debris that will get in there and gunk up those connections. So you can also kind of use this to help bundle up that wiring at the back of your hitch, if there's extra, and keep everything together.As far as the specs with this, for the amperage it has a max amperage for the stop and turn lights of three amps per circuit, and for the tail lights of six amps per circuit. It is covered by a one year limited warranty, and that's about all there is to it for our quick look at the Curt T-Connector Vehicle Wiring Harness. I hope this video has been helpful in deciding if this is the right one for you. Again, I'm Ellen here at etrailer.com, thanks for watching.

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C56148

Average Customer Rating:  4.9 out of 5 stars   (13 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.

- C56148

Great product and super easy install

- C56148

Ordered a trailer hitch assembly for my Honda CRV. etrailer's instructional video was excellent - tailored for my exact vehicle. It made the installation very easy.

- C56148

A great source from hitch to lights watched the videos ,easy install ,saved a bunch of money, thank you Eric

- C56148

Install went fairly easy. There's definitely a bit of creative wire tucking involved, but nothing the every day DIYer can't handle. Worked great.

- C56148

Great product, easy installation, etrailer delivered!

- C56148

Put in an order Got conformation and tracking info Parts arrived Now all installed And they have YouTube instruction videos

- C56148

Great kit, works flawlessly, highly rec ommends

- C56148

Very easy to do, step by step instructions. basic electrical knowledge is helpful but not necessary. Whole job took about an hour.

- C56148

Perfect fit

- C56148
2014 Nissan NV 3500

- C56148
by: 08/08/2021

- C56148

- C56148


Ask the Experts about this Curt Custom Fit Vehicle Wiring

  • Installation of 4-Pole Wiring Harness in 2017 Nissan NV 3500
    To install the T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56148 in your 2017 Nissan NV 3500 you only need to plug it into your Nissan's tail light wiring harness, which you can find in your van's rear cargo area and then wire a hot lead to the battery. I have added a cut out of the directions for you to check out, and the full installation instructions are also linked.
    view full answer...
    Image 1 for
  • Recommended Wiring Harness for 2014 Nissan NV 3500 Passenger Van
    The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56148 is a confirmed fit for the Nissan NV 1500, 2500, and 3500 models between 2012 and 2020. There is not a separate fit for the cargo models from the passenger models because they utilize the same wiring. You can alternatively use # 118553 or # HM11143585 which are also confirmed to fit. These are all good options, so I recommend going with the best cost at that time of purchase.
    view full answer...
  • Hitch & Brake Controller for 2016 Nissan NV 2500
    We do offer a 2-inch Class IV hitch for your 2016 Nissan NV 2500, the Curt # C14000. This hitch offers no-drill installation. Installation on an NV 3500 is shown in the linked video. You will also need a ball mount and hitch ball. The linked article will help you determine which ball mount you need. Use a hitch ball of the size and weight rating required by your trailer. For a brake controller to activate the trailer's electric brakes I suggest the reliable Prodigy P2 # 90885. If...
    view full answer...
  • What Do I Need To Tow a Car Hauler Trailer With My 2012 Nissan NV 2500?
    Yes, the Draw-Tite Max-Frame Trailer Hitch Receiver # 75715 will work for your 2012 Nissan NV 2500. Your Nissan will have a tow rating between 7000lbs and 9500lbs. You can contact Nissan for your exact tow rating by VIN number. The Draw-tite will allow for up to 7,000lbs towing and 1,125lbs of tongue weight. If you are using a weight distribution hitch the ratings are 10,000lbs towing and 1,000lbs of tongue weight. You will want to verify the weights of both your VW Passat and U-Haul...
    view full answer...

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Info for this part was:

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Employee Jacob T
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