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CURT

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

Part Number: C56040

3905 Reviews

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$48.22

Retail:$62.99

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1 used item available at $38.11

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2012 Kia Optima

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curt custom fit vehicle wiring trailer hitch 4 flat t-connector harness with 4-pole connector

curt custom fit vehicle wiring trailer hitch plug-in

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In Use/Installed

2009 subaru forester custom fit vehicle wiring curt end connector 4 flat c56040

2009 subaru forester custom fit vehicle wiring curt trailer hitch plug-in on a

2009 subaru forester custom fit vehicle wiring curt end connector 4 flat on a

2009 subaru forester custom fit vehicle wiring curt trailer hitch 4 flat c56040

2009 subaru forester custom fit vehicle wiring curt trailer hitch 4 flat t-connector harness with 4-pole connector

0 custom fit vehicle wiring curt 4 flat plug-in c56040

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Videos

Curt T-Connector Vehicle Wiring Harness Installation - 2022 Subaru Forester

Curt T-Connector Vehicle Wiring Harness Installation - 2023 Subaru Forester

Curt T-Connector Vehicle Wiring Harness Installation - 2024 Subaru Crosstrek

Curt T-Connector Vehicle Wiring Harness Review C56040

Curt T-Connector Vehicle Wiring Harness Installation - 2024 Subaru Forester

Curt T-Connector Vehicle Wiring Harness Installation - 2023 Subaru Outback Wagon

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SCHEDULE AN INSTALLATION

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. 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 C56040 or order online at etrailer.com. 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.

CURT Custom Fit Vehicle Wiring - C56040

Highlights

Custom Fit for Your Vehicle: Works with your vehicle's wiring
Tow Without Factory Prep: 4-pole connector powers trailer turn, brake, and tail lights.
Plug-and-Play Install: T-connector plugs into rear harness—no cutting or splicing needed.
Protects Vehicle Wiring: Powered converter isolates circuits to prevent overloads or shorts.
Higher Light Output: Handles 3 amps per stop/turn and 6 amps for tail lights for brighter signals.
Clean Mount Option: Harness can route through rear grommet to mount near hitch for easy hookup.

Features to know about

Installs Fast with Plug-In Design: No Cutting Into Factory Wiring

This Curt T-Connector makes wiring simple. It plugs right into the vehicle’s factory connection behind the rear trim panel, so you don’t have to cut or splice anything. The factory-style connectors click in place for a clean, hidden setup that’s ready to use right away.

Delivers Reliable Power for Trailer Lights: 3 Amps Stop/Turn, 6 Amps Tail

The built-in powered converter supplies up to 3 amps per stop/turn circuit and 6 amps for the tail lights. That higher output capacity helps keep your trailer lights bright and working properly even when towing trailers with extra lighting or long wiring runs.

Ready to Tow Small and Medium Trailers: Standard 4-Flat Output

The 4-flat connector gives you the basic trailer light functions—running lights, brake lights, and turn signals. It’s the common plug used on small and medium-size trailers, so you can hook up and head out without extra adapters.

Expands Easily for Future Upgrades: Works with 7-Way Conversion Kits

When you’re ready for a brake controller or need a 12-volt charge line, this harness can be expanded using kits like the ETBC7 or ETBC7L. That means you can start with a simple 4-flat setup now and upgrade later without rewiring your tow vehicle.

Subaru OEM trailer hitch receiver assembly installed on vehicle showing receiver tube and bumper fitment

Specs

Electrical Specifications

Output per stop/turn circuit: 3 amps
Output for tail lights: 6 amps
Fuse: 10 amp fuse inserts into the red fuse holder located on the red wire between the white plug and the black converter box

Compatibility

Part number: C56040
Connector type: 4-pole flat trailer connector
Vehicle connector location: Rear cargo area, typically behind interior trim panel on driver’s side
Fits: 2010–2025 Subaru Outback Wagon, 2013–2023 Subaru Crosstrek (non-hybrid), 2014–2025 Subaru Forester, 2018–2025 Subaru Ascent
Not compatible with: 2014 Subaru Impreza Hatchback

Design and Construction

Type: T-Connector Vehicle Wiring Harness
Manufacturer: CURT
Facets: Hidden, Plug-In, Plug and Lead, Trailer Hitch Wiring, Vehicle End Connector, Powered Converter, No Tow Package, 4 Flat
Installation: Plug-and-play, no splicing required

Comparison image showing Curt C56040 trailer wiring harness and Tow Ready 118467 wiring harness side by side with labeled parts and connections for Subaru vehicles

Notes on Operation

Converter function: Powered converter isolates trailer circuits and protects vehicle wiring
Ground connection: Separate ground wire must be installed
Mounting option: 4-flat connector may be routed through rear hatch or through grommet near spare tire for external mounting

Note

Additional information: Part # C56040 can be combined with Universal Installation Kit # ETBC7L or # ETBC7 to convert to a 7-way for trailers with electric brakes or for charging trailer-mounted batteries. Not for hybrid models.

56040 CURT T-Connector - Surface Mount Technology - 4 Wire

Similar to Tekonsha 118467 and Hopkins HM11143885

Installation Details C56040 Installation instructions

This Product Fits The Following Vehicles

2019 - 2028 Subaru Ascent
2019 - 2028 Subaru Ascent
2016 - 2028 Subaru Crosstrek excluding Hybrid
2018 - 2028 Subaru Crosstrek excluding Hybrid
2018 - 2024 Subaru Crosstrek Hybrid
2024 - 2028 Subaru Crosstrek Hybrid
2016 - 2017 Subaru Crosstrek non-Hybrid models
2009 - 2028 Subaru Forester
2009 - 2028 Subaru Forester
2026 - 2028 Subaru Outback
2013 - 2025 Subaru Outback Wagon
2013 - 2025 Subaru Outback Wagon
2010 - 2012 Subaru Outback Wagon excluding Sport
2010 - 2012 Subaru Outback Wagon excluding Sport
2013 - 2013 Subaru XV Crosstrek
2013 - 2013 Subaru XV Crosstrek
2014 - 2015 Subaru XV Crosstrek excluding Hybrid
2014 - 2015 Subaru XV Crosstrek non-Hybrid models

Customer Satisfaction Score:

98% were satisfied with this product

2% of customers were not satisfied

Product did not meet expectations
Wrong item was ordered
Did not arrive in time

2% of customers were not satisfied

Product did not meet expectations
Wrong item was ordered
Did not arrive in time

4.8

3905 reviews

5 Stars		(3456)
4 Stars		(315)
3 Stars		(59)
2 Stars		(32)
1 Star		(43)

by: John 08/23/2026

2023 Subaru Outback Wagon

Just got a new to us 2023 Subaru Outback. Right away went onto etrailer and ordered the Curt Trailer hitch and T-connector for the vehicle. etrailer had an excellent video on their website for both the hitch and wiring install. The video clearly showed the install. Even though I've got 45 years of mechanical experience, the video clearly showed me how to do it. I followed it to a T and the overall install time was about 90 minutes. The etrailer video for the wiring harness was actually better than the included instructions! Ordered everything on Thursday evening about 6pm with a expected Monday delivery. Surprised when everything arrived Saturday afternoon! WOW. skip Amazon and go with etrailer!

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Christopher H.

8/25/2026

Congrats on the new Subaru John and thanks for the kind words and including photos! Glad this was a smooth installation and we could get it to you a little quicker than expected. What are your plans for the hitch?

by: Craig 05/28/2026

2026 Subaru XV Crosstrek

Easy install. I can confirm that this product works for the 2026 Crosstrek Hybrid. The factory plug is easy to locate under the lower hatch trim. I also bought a Curt 58405 4-pin adapter that fits the license plate light hole in a metal truck bumper, made a 1.125" hole in the bottom of my bumper cover, routed it through an existing pass-through to the trunk. I did have to cut the wiring on the T-connecter to splice this one in. Highly recommend the Curt wiring harness for true plug-and-play, and recommend etrailer as the best source for hitches, accessories, information and how-to videos.

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by: Neil D 08/12/2026

All parts arrived perfectly and were securely packaged. I opted to install the trailer package myself and completed it with no problems at all. I would definitely order from etrailer again for sure.

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by: Felipe 08/08/2026

Very good hitch, I will give it 10 out of 10. Factory look and installation.

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Kate F.

8/10/2026

Install looks FANTASTIC Felipe! What do you plan on towing with the new set-up?

by: Dan F. 11/25/2024

2024 Subaru Ascent

I bought this wiring harness for my 2024 Subaru Ascent. This harness was easy to install even though it didn’t come with instructions. The length of the wire connecting to the 4-way plug was the correct length with about 8 inches to spare and plugged right into the connector on the vehicle. I would recommend this product.

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Dan F. One Year Later

11/27/2025

I haven’t had any issues with the wiring harness, I’ve pulled many trailers and the connection to trailer lights are tight.

Chris R.

11/29/2025

@DanF Fantastic! Here's to many more brightly lit years.

by: Richard 10/31/2025

I bought a hit hitch and wiring harness for my 2019 Subaru and the hitch went on well. The wiring harness was bone easy to connect BUT, finding where to plug it was not as simple as the instructions made it sound on my car anyway. I had to remove the back seat bottom (locate clips on each side and pull sharply straight up) and then remove the bolt holding the side bolster (between door opening and seat back) and then remove the bolt located below the cover on the rear compartment tie-down ring (pry up lower central bit) to get the side trim piece loose enough to allow my arm in to snap the connector into the factory harness. Nothing terribly involved but the instructions say something like “locate the wiring harness and install connector and ground wire” but don’t mention what I have indicated above. I grounded the white wire to the tie-down ring bolt before putting that back together.

This is the third hitch and second wiring harness kit I have bought from ettrailer.

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by: kdpnw 10/08/2026

2021 Subaru Forester

Thousands of people have already reviewed this hitch favorably. Nothing more I can add other than to echo that it’s a fine hitch that a 70-something can install by himself with the assistance of eTrailer’s excellent installation video for a 2021 Subaru Forester.

Ordering and shipment were easy. Great experience all around.

by: Grant 11/08/2025

Excellent quality, fit perfectly in place. Little nervous about dismantling the rear my new Outback (and my wife was more nervous still), but the video was very clear and complete. Only oddity was the bolts I took out to remove the bumper frame had 17mm head and the bolts supplied to replace them needed 11/16” wrench. Still, all parts needed were there, and the fish wires (I only needed one) were phenomenal, making what would have been the most frustrating part of the job almost comically simple.

I appreciate that you've clearly thought through everything you can provide to make installation easy and successful.

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by: Jeff L 05/15/2025

This is the first devoted trailer lighting harness I've ever installed, and I'm not sure I'll ever go back to splicing and soldering if I don't have to.

This harness simply clicked into a hidden plug in the trunk area behind the trim (I had NO idea this plug even existed on the Subaru), and that was that. I tucked the wires and control box away, reinstalled the trim, and gave it a successful test run...everything works, everything looks clean and tucks away when not in use...almost too easy!

Jeff L. One Year Later

5/13/2026

I had absolutely ZERO issues with this harness when I was using it! Everything went together seamlessly and worked flawlessly. And THEN...the transmission went. So its bye-bye to this car anyway. BUT...Ill definitely give this kind of harness a try again in the future if the situation arises!

by: Travis (22 outback) 10/18/2025

Connector is correct, but directions are way off. Needs to be updated. The OEM plug is not in the same place as previous body styles. I chose not to close the wiring in with the trunk because that’s a dumb idea. There’s a supplied hole with a grommet right next to the OEM plug. Makes it easy to pass wires through and be right on top of the hitch. And there’s a fantastic spot for body ground, that doesn’t require running a self tap screw into the car. Will attach pictures.

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by: Carter453 05/25/2024

2018 Subaru Forester

Came as fast as lightning, the instructions for a 2018 Subaru forester were incorrect, the plug assembly is tied up on the drivers side aft most side wall panel, pictures added, not on floor as shown in the instructions and on etrailers video, took a bit of hunting to find it, but after that it took more time to clean up.

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Carter453 One Year Later

5/26/2025

Works as advertised!

by: Bob 08/19/2026

Subaru Forester

The trailer hitch is well made and seems very strong. The installation instructions are not correct for a 2024 Subaru Forester Wilderness. There are no bolted straps securing the muffler. Two welded rods with rubber grommets secure the muffler. The muffler must be disconnected at the joint and then pull the muffler out of the rear grommet to move out of the way to access the frame.

by: Tony 10/12/2026

2014 Subaru Outback Wagon

The videos are exceptionally helpful! ETrailer is a fantastic company. Very happy with the quality of the product and even more satisfied with how well they put it all together and make it so an avg skilled person can install.

by: Ronald D 02/28/2025

2025 Subaru Outback Wagon

Works nicely on my 2025 Outback. I chose to do my installation a little differently from the video as I don’t like pinching the wire in the tailgate. There is a rubber plug in the upper right side of the spare tire well that is suitable for the wire to go through, but it is not big enough for the harness plug, so cutting and splicing wires was required. The supplied butt connectors are too big for the wire size so I bought some 14-16 gauge(blue) connectors for the job. The ground lug for the module is way too big for the self-tapping screw so I added a washer under the head of the screw for a good solid connection, which is important for proper operation of the module. Be sure to seal the slit in the rubber plug around the wire with silicone sealer to prevent water or carbon monoxide entering the spare tire well.

Ronald D. One Year Later

3/4/2026

Still working good

by: Dick M 08/18/2026

2013 Subaru Outback Wagon

hey the receiver is solid, perfect fit! the wiring kit also great.. instructions def need updated to match late model car (2025 outback XL touring) 13 not 7 body buttons,of three different sizes! keep track for ease of reassembly! I was able to reuse all 13. i'm a mechanic, not for your average joe...js

by: Randall 09/20/2026

2016 Subaru Outback Wagon

Subaru has made the trailer wiring harness so much easier to install on the 2025 than my previous 2016 Outback.

by: James Crawford 05/12/2025

Subaru Forester

Etrailer has been excellent in all aspects of purchase, guidance and customer service. I bought a trailer hitch and wiring for my Subaru Forester. I have never done anything like this, and with etrailer I had uncomplicated and satisfying success.

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Gwendolyn Y.

5/13/2025

High-five on the install, James! It looks great. What kind of towing plans do you have?

James C.

5/13/2025

@GwendolynY hey! My uncle has a small boat just big enough that it needs a trailer, now he has me to tow it. Also plan on getting a bicycle rack! Thank you!??

Gwendolyn Y.

5/13/2025

@JamesC That's awesome that you will be able to do that for your uncle, James. Do you already have a bike rack you can use? If not, we do carry those too, there are A LOT of options so if you do need help when looking at them let me know. I can help make the task less daunting.

by: Richard 09/28/2026 One Year Later

nice trailer hitch set up. sure better than orig equipment mfr price

by: Aaron W 07/01/2026

2021 Subaru Outback Wagon

etrailer suggested the wrong wiring harness to go with my hitch receiver. To return it, I had to pay shipping myself - $14 - on a $42 part. They also said the original shipping cost will be deducted from my refund. So I am losing money to fix their mistake. Next time i will use someone else.

by: Gary 05/13/2026

I'm embarrassed to tell this but I purchased the hidden hitch for my vehicle only to discover after removing the bumper fascia that someone had installed the exact hitch before I bought the vehicle. The company was very helpful in my returning the brand new hitch to them.

Kate F.

5/14/2026

It happens more than you think Gary =)

by: Mathew 08/08/2026 One Year Later

Love this hitch. We travel a lot with our bikes, but also ride off-road. This allows us to take off the hitch to ensure it “doesn’t scrape” when we are on backroads and off-roading.

by: John 09/14/2026

Easy install. Works great. Would have given it 5 stars if there was a better solution for mounting to the hitch itself so I don’t have to take everything out of the trunk to use. Otherwise great product.

by: Bryce 08/25/2026

2010 Subaru XV Crosstrek

Super quick install in 2024 crosstrek sport using provided video. Plugs right in, 1 self-tapping screw... 10 minute install job, tops!

by: Kevin 07/23/2025

Easy installation! No cutting or splicing. Installation video was quite helpful. However the video recommended not routing the harness to the trailer through the floor and risk contacting the exhaust. My 2018 Crosstrek had an existing port covered with a gasket. I used a drill to slightly open one side of this access to allow the connector to pass. This route is between the bumper rail and cover, avoiding the exhaust. I finished up with cable ties near the hitch with existing holes in the bumper.

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by: Travis 09/27/2026

2022 Subaru Ascent

Quality part, appreciate the extra parts for installation, great installation video's!

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Condition: Like New

Notes: May have damaged packaging or minor cosmetic blemishes.

$38.11

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