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Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector

Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector

Item # C56107
Our Price: $33.66
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Custom Fit Vehicle Wiring

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Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. Connector plugs into OEM tow package port - no cutting, splicing or tapping required. Converter is made using SMT to ensure superior performance. 1-800-940-8924 to order CURT custom fit vehicle wiring part number C56107 or order online at Free expert support on all CURT products. Great prices and Fastest Shipping for Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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  • Reviews (83)
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CURT Custom Fit Vehicle Wiring - C56107

  • 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. Connector plugs into OEM tow package port - 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
    • Designed for use with a factory tow package
    • 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
  • Limited 1-year warranty


  • Amperage allowance:
    • 3.0 Amps per turn/brake
    • 6.0 Amps per taillight function


This custom-fit T-connector plugs into your vehicle's factory tow package 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 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 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.

56107 CURT T-Connector - OE Replacement 4-Flat - Surface Mount Technology

Installation Details C56107 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector - C56107

Average Customer Rating:  4.9 out of 5 stars   (83 Customer Reviews)

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

2004 Toyota Highlander

A couple of Saturdays ago I installed the C56107 Curt T-Connector Factory wiring harness for Factory tow package on my 2004 Toyota Highlander.

The installation was very easy once I removed all of the panels in the back of the Highlander. I purchased this vehicle new in 2004. The dealer showed us how the 3rd row seating would look by setting up the third seat. Since that day I've never had the cause to open it up again.
Once all of the panels were removed I quickly located the factory plug. It only took a second to plug the connectors together. Using the two-sided tape provided I stuck the controler to the outer fender wall. I cut a hole in the side of the small bin to allow the plug entrance to the bin. If you don't have a rollup cover that fits just in front of the jack holder you might not have to perform this step. I'm not sure. From that point it was just a matter of reinstalling all of the parts removed.

All parts of the trailer lights controller worked perfectly. I tested it with a plugin tester following the install. I did have to add a 20 amp mini-fuse to the box under the hood.

I've attached several pictures that I took along the way.

Thanks for a great product. I recommend it highly.

2006 Toyota Highlander

Works well and easy to install on my 2006 Highlander that was 'Tow Ready'. Call dealer to verify by the VIN. Don't forget to have 20A fuse for vehicle fuse panel. It would be nice if they included the fuse.

2010 Toyota Highlander

If your Highlander already comes with the factory tow package this Curt wiring harness is the quickest and easiest to install. I used the installation video for the Tekonsha wiring harness with tow package which was great. The advantage of the Curt wiring harness over the Tekonsha is that you don't have to install the white ground wire. You simply access your factory tow wire, plug in the Curt wiring harness and that's it! And if you don't have a 20amp mini fuse already in your car fuse box in the tow spot then you will need to pop the hood and put one in which takes about 10 seconds. Best plug and play option available.


As a retired mechanic I have never had such an easy install ever !! Great product unbelievable easy. I would recommend it 100% to anybody who’s interested in one.


So easy to install!! My car already had the jack/plug. Just plug it in and ground on an existing body bolt right there next to the plug. Your ready to tow. Thank you for making this so easy.

2013 Toyota Sienna

Excellent product, clicked right into the factory connector. No cutting or splicing. Could not have been more simple.


To be honest, I don't remember what vehicle this is for, as I have installed several hitches on friends and families vehicles.
To say the least, etrailer is THE place buy hitches and light kits, as they are the best price, the quickest shipper AND the videos they provide that explains the installation, they are a "tree-men-dus" (said with excitement!) help! All the hitches and light kits I buy and install a "stupid" easy to do! All the hitches and light kits are of high quality and will outlast the vehicle they are installed on!

Toyota Highlander

Best, most reliable place to get what you need, for your trailer. Efficient, effective website offers perfect specifications tailored to your particular vehicle. I quickly found a custom pigtail electric harness for my old (2007) unusual (hybrid Highlander) Toyota that had a built in fuse (protecting my car fuses) and a plug-in that fit to my vehicle wiring harness exactly. Quick shipping and handling, and great personal attention when you need it! I'll be back, and highly and unconditionally recommend etrailer.

Still doing great!
Archie - 12/08/2018


Plug and ready to go


My trailer lights are working fine thanks to a swiftly delivered, perfectly functioning adapter I received from etrailer. The installation instructions were enclosed with the product. I am fully satisfied and ready to roll!

It is great. I have had no problems. The connector and wiring were good quality materials that show no signs of age or weathering. I use a trailer fairly often. It was easy to install and easy to use.
David C - 06/04/2014

2005 Toyota Highlander

Very easy to install. Directions were g reat

Toyota Highlander

We were very pleased with our trailer wiring harness for our Highlander it was very quick and easy to install since we had a connection in the back of our Toyota just plugged it in and hooked up the trailer and ready to tow our trailer. No headache of figuring out the wiring system and rewiring. Thank You so much. We are a very happy customer and will be back as a need arises.

2007 Toyota Highlander

This installation was literally a snap to put together! All I did was snap the connections together, snap in a couple of fuses and secure the adapter to the inside of the trunk space. I had such a difficult time trying to find a wiring harness that I could install myself for my 2007 Toyota Highlander Hybrid with tow package before finally coming across the experts at etrailer! I had been thoroughly confused by the other website's wiring harness determination for my vehicle and had to return the initial one I had purchased from them because it wasn't for the hybrid even though it said it was. I was also quoted over $300 at my local Toyota dealership for the harness, wiring and labor installation. Then I was quoted over $200 from the trailer rental place, where I would have had to drive about 3 hours away for the installation. These were not ideal options for me, or anyone for that matter. I emailed etrailer after months of reading threads about how other people were having the same problems I was with locating the correct wiring harness for my specific vehicle. They were prompt in their response and very thorough in their suggestions and pertinent information for the wiring harness I needed. The part and shipping ended up costing me less than $30! I'm EXTREMELY HAPPY with my purchase!!!

2007 Toyota Highlander

Haven't used with a trailer yet, but will do so in a few weeks. Vehicle is a 2007 Toyota Highlander hybrid. Directions are not completely clear which of the three (or that there would be three possibilities) connectors in the vehicle to use. First two are much more visible, but are incorrect. After digging around in rear of vehicle, found the third correct connector. After that, it was very easy to install. Tested with multi-meter and appears to work correctly with flashers,turn signals, and brake lights.would be nice if these were labeled for the flat 4 plug connector to make testing and any troubleshooting easier.

2005 Toyota Highlander

Overall my experience was excellent. The videos helped me fit the hitch and wiring. The job was done in less than an hour. I recommend looking at videos and keeping them close especially during wiring. Not difficult but get details right first time to avoid going back!
One caveat with this. I wish it was in bold letters that hitch pin does not come with the three mounted ball. I put the whole thing together and because I did not buy the hitch pin( thought it came with three ball mount) I could not use the hitch straightaway. You would think they should add small amount of money to ball mount and throw in hitch pin in the box!!!!


Easy to install, wiring connections worked as advertised. Hitch receiver is very well made.


I bought a simple connector from about a year ago. I'm writing this review because they actually followed up with me after all that time to make sure I was still satisfied.

Let's face it, a connector isn't a major purchase. It's small and simple enough to warrant taking a risk of gettting burned on a bad product. So, this review isn't about the product. It works as described and has survived a year of frequent use an abuse. Besides, you buy something online and you have plenty of info if you do your homework. a quick search will tell you everything you need to know about how well it works and what it's pros and cons are.

What is less known is the person selling it to you. Anyone can start up an ecommerce company in a few minutes, and there are no shortage of scammers taking customers for a ride and folding up shop to reopen later that day under a new name. Reputation is everything in the online retailing game, and that's what this review is of -

I buy things online all the time. In fact, I do the majority of my shopping online unless it's something I need ASAP. I've done buisness with hundreds of retailers. Guess how many went the extra mile to ensure I was satisfied after an entire year? Yep, ONE. Don't get me wrong, a good 50% of all retailers will contact you a week or so after your purchase to beg for a good review. Generally, I'll oblige if they went the extra mile on shipping, package, or something else. It's not that I am stingy with praise, I just don't believe in leaving a good review is all I have to say is "everything went as expected" because I don't think not getting burned and having someone hol dup their end of a very simple bargain is 5-star review worthy, and if you're not leaving 1 or 5 starsm what's the point of the review? It's not helpful to the retailer or potential buyers and it's all just white noise.

So here's my 5 star review of - The item was reasonably priced (why I bought it), arrived fast and in it's original retail packaging. They checked in with me to make sure the item did what I wanted it to do and arrived unmolested after about a week, and again after about a year. Not to beg for a review but to, "make sure [I] like the product after owning it for a year." They left multiple contact info, which tell sme they actually give a rip about hearing back from me. I expect that if I replied and told them the product was garbage that they would evaluate carrying it all together and probably do whatever they reaosnably can to replace it.

No need, the product works great and I am entirely happy with my decisiont o purchase it form

Toyota Highlander

I will never buy anything else but this product ever again. I bought this hitch and a Curt custom wiring kit for my Toyota Highlander. So easy !!! everything plug right in and bolted directly up in my driveway. NO KIDDING. I installed both hitch and wiring in 30 minutes Flat !!!! Excellent. Im no mechanic !

2005 Toyota Highlander

After spending a number of calls to a couple of dealerships trying to order a factory wiring harness for my '05 Highlander, my frustration finally met its limit! Not only was I given wrong part numbers, but it wasn't until the third call that I was informed that the part was no longer available.

Your harness was what I needed. It even has an in-line fuse! It fit the factory connectors...I am very pleased. I didn't mention that the price was much more agreeable as well.

2005 Toyota Highlander

Very fast free shipping of a large heavy package, ordered Wed am and had it Fri afternoon to Duluth, Mn area. I have ordered Curt Hitches from before and have always been very impressed with the quality. The c56107 vehicle wiring harness works great with the factory connector as my 2005 Toyota Highlander was ordered with the Tow Package prewired option. The web site is very user friendly and they provide great service.

Toyota Highlander

Received the wiring harness from etrailer yesterday and installed it in less than 30 minutes. The Toyota dealer wanted $147 for the wiring harness and $87 for the installation fee = $234 total part / installation. The most difficult part of the installation was getting the cover panels off of my Toyota Highlander so I could access the plug in connection. The entire process was made very simple by the video and written instructions on-line at etrailer. Very happy with the entire process from ordering to installation. Great service and price at etrailer....will do business with them again!!!


After my existing "taillight converter" shorted out, I searched the internet for a replacement. I found the etrailer website to be unusually well-organized. I especially liked the feature that verified that the product matched my vehicle and the video showing installation. I liked the tracking function for the shipment. I took the replacement to my local trailer repair shop, and they installed it in an hour with no problem.

2005 Toyota Highlander

Very simple install. Haven’t tried it yet but hope to soon.


So rarely these days does someone actually get to buy something that is supposed to be a direct fit and guess what? It actually is, the trailer wiring package just plugged right in.

BTW, your product documentation went over and above. Giving good instructions on removing a couple of interior panels to get at the trailer light connector and also recommending to check the fuse box "towing" fuse as it may require a 20A mini-fuse to work.

2004 Toyota Highlander

Simple plug-in installation. The hard part was taking panels off, but if you take your time, you'll be okay.
I'd watched the video for installation of a kit for vehicles WITHOUT the tow package, but my vehicle has the tow package, and I ended up taking stuff off the car that I didn't need to.
So, be careful that you watch the exact video yo need.
The wiring kit is well made and fits as it should.

Show More Reviews

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

  • Troubleshooting Curt T-One Connector on 2007 Toyota Highlander
    Is this a brand-new installation, or has the T-Connector been installed for awhile? As a first step, I would recommend trying a different trailer, if possible. This will help determine if the problem is in the trailer wiring or that of the vehicle. If everything works fine with another trailer, then you have confirmed that the problem is in the trailer wiring. If the lights on the second trailer do the same thing, you have confirmed that the T-Connector is faulty and should be replaced....
    view full answer...
  • Wiring Harness for 2007 Toyota Highlander Hybrid
    It definitely looks like you found the right connector for a tow package on your 2007 Toyota Highlander Hybrid! With this being the case I recommend using the Curt T-Connector # C56107 because it has higher amp ratings than the Tekonsha T-One # 118248. This will fit directly to the connector in the picture that you submitted. Attached are the installation instructions for you to check out.
    view full answer...
    Image 1 for
  • Which Vehicle Wiring Harness For 2007 Toyota Highlander V6 2WD?
    I would be happy to help! For your 2007 Toyota Highlander V6 2WD you will actually need the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118413 which plugs into the back of your tail lights as you can see in the included video. The reason the two connectors on the # C56217 and # C56107 were incorrect is they are for models with the towing package, where your Highlander appears to not have the towing package. I included a video of the # 118413 being installed on a...
    view full answer...
  • How to Determine if 2006 Toyota Highlander Has the Factory Tow Package
    If your Highlander has an active tow package plug located in the driver's side rear of the cargo area under the floor (see linked instructions for part # C56107 to see where plug is located and how to access it) your Highlander has the tow package. If you find the plug, use a circuit tester like part # PTW2992 to ensure it's active. Probe the contacts of the plug as a helper activates each lighting function. If you don't find the plug, or if it's NOT active, you don't have the tow package. There's...
    view full answer...
  • Trailer Wiring Harness Causing Dash Warning Lights on a 2005 Toyota Highlander
    First let's make sure you have the proper trailer wiring harness. Tow Ready harness # 118413 is designed for all models of the 2005 Toyota Highlander EXCEPT for hybrid models. If you have a hybrid model this harness is not a correct fit. For a hybrid with factory tow package you would use # C56107. Next check the connections where the harness plugs into the vehicle. Look for broken or bent pins. This could cause malfunctions or shorts. If you do not see anything out of the ordinary, plug...
    view full answer...
  • Vehicle Keeps Blowing Fuses When Headlights Turned on with Trailer Connected
    You're likely on the right track. If your fuses keep blowing out, this is a sign that there is a short somewhere on the system-most likely on the running light circuit. Since you're saying that the trailer has all new wiring-if this was something you installed I would recommend re-checking your wiring to make sure that there isn't an exposed wire (cut, damaged or otherwise) touching the frame of the trailer. The ground wire on the trailer should be checked to make sure it is secured to...
    view full answer...
  • Recommended Wiring Harness for a 2004 Toyota Highlander With a Factory Tow Package
    The 2 options for a 4-Way wiring harness that you have for your 2004 Toyota Highlander are just different manufacturers. Out of the Tekonsha T-One Wiring Harness # 118248 and the Curt T-Connector Wiring Harness # C56107, I recommend going with the Tekonsha version as Tekonsha is one of our most reliable wiring companies. I have attached a video of the T-One harness being installed on a 2004 Highlander for you to reference as well. If you are needing to install a 7-Way wiring harness at...
    view full answer...
  • How To Determine If 2003 Toyota Highlander Has The Factory Tow Package
    if your 2003 Toyota Highlander has a tow package plug located in the driver's side rear cargo area under the floor (see instructions for installing Item # 118413 on where to look) then your Highlander has the tow package. If you find a plug, use a circuit tester like Item # PTW2993 to check to see if it is active. If you do not find a plug or the one you find is not active, then you do not have a tow package. Another way to find out is to contact your local Toyota dealer, give them...
    view full answer...
  • Which Trailer Wiring Harness for 2007 Toyota Highlander
    The correct trailer wiring harness for your Highlander will depend on whether or not it is equipped with the tow package and the lighting set-up of the trailer you will be towing. If your Highlander has the tow package, and you will be towing a trailer with very basic lighting (one stop/turn/tail light per side) then the Tow Ready # 118248 would be a good choice. If your lighting is a bit more complex, you would need a harness with a higher rated converter like the Curt # C56107. If you...
    view full answer...
  • How to Determine if 2006 Toyota Highlander has the Factory Tow Package
    There are a couple of ways to determine if your 2006 Toyota Highlander Hybrid has the factory tow package. First, you could call a Toyota dealership and have them run the VIN through their computer system and they should be able to tell you how the vehicle is equipped. If they can't for some reason then you can look for the port on the vehicle where a trailer wiring harness, such as # 118248, would install. You can use the video I have linked to locate it. Then you can test the pins on...
    view full answer...

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