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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 # C55585
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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 - no cutting, splicing or tapping required. Converter is made using SMT to ensure superior performance. 1-833-496-1390 to order CURT custom fit vehicle wiring part number C55585 or order online at 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 (55)
  • Q & A (0)
  • Photos
  • Why etrailer?

CURT Custom Fit Vehicle Wiring - C55585

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • 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 - 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
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Connects quickly and easily - no cutting or splicing of wires
    • Locate connection points behind tail lights
    • Plug in T-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


  • Maximum amperage:
    • Stop/turn lights: 3 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 behind the driver's-side and passenger's-side tail lights. You will have to remove the tail light assemblies to access this harness.

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.

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.

55585 CURT T-Connector - Surface Mount Technology - 4 Wire

Installation Details C55585 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 - C55585

Average Customer Rating:  4.9 out of 5 stars   (55 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 - no cutting, splicing or tapping required. Converter is made using SMT to ensure superior performance.


Some of the wiring could be longer, others shorter. Would be better if the transfer box had a solid mounting point vs 2-sided foam tape. Also had to remove the white plastic inner spacer for the connector on the passenger side plug that goes into the tail light (easy to do with a pair of needle nose pliers).

Overall very easy to install and built decently.


Great to have all the components at the same time. Quality at a good price!

2009 Honda Ridgeline

I haven’t installed it yet, but it looks like a good, well-made product.


Product itself is good. The install directions are probably useful for someone who's installed this same item on the same model vehicle before. They are not very useful for someone doing it for the first time on this model vehicle and likely useless for a relative neophyte. Specifically, everything after step 4 (of 8) is useless.

Thank you for your feedback. We do have a video installation on a 2008 Honda Ridgeline that is helpful.
-- Etrailer Expert Jenny N - 11/02/2021


works just the way I expected


The reason this one is excellent is because I haven't installed it yet. I live in the rust belt and 2 of the exact same products failed due to exposure to the elements and salt/sand treated roads. The first one worked well for a couple of years but shorted out somehow and subsequently shut down my vehicle tail and brake lights in the middle of a snow storm while driving at night. When the first one failed the manufacturer replaced it free of charge but that one eventually gave in due to the elements also. When I called the manufacturer they reluctantly promised to send me another but didn't come through or tell me why. The reason I bought the 3rd unit is ease of installation which I haven't done yet but will the next time I do any trailering at night. It's the black converter box that shorts out.

2006 Honda Ridgeline

Excellent instructions and wiring harness fit perfectly with no problems whatsoever. Took about 45 minutes to install completely.

I dont use the hitch all that much but it works fine.
Jim A - 11/01/2017

Honda Ridgeline

The wiring harness was easy to install on the Ridgeline. It took about 30 minutes most of which was removing and re-installing the tail light assemblies. The wiring runs were of good length to route them. The materials are of excellent quality. The instructions were simple to follow for the installation. Recommend this to any Ridgeline owner lookin for a quick wiring kit for your truck.


Very easy install hardest part was disconnecting original taillight plugs !

Ford Flex

It was just what I was hoping for. Instructions were helpful, easy to install. The connector on the right side had me stumped for a bit, the wiring connector would not plug into the trucks connector. I realized the wiring connector had a stiff white plastic spacer that was not needed for my application. I pulled it out and the connectors snapped right together. I put the wiring in a plastic flex type hose and zipped tied to the body above the hitch.

2013 Honda Ridgeline

Super easy installation with the video and it works as advertised. Saved me a lot of money vs. having UHaul or Pep Boys install a wiring harness. The only negative, the adhesive pad did not hold for long, ended up zip-tying the module to the undercarriage.

2008 Honda Ridgeline

This wiring kit was a breeze to install. Just remove the taillights hook up the new connectors and run the wires. I tested it and it works great. Over the years I have ordered several items from and I have always had fast services and quality products. The reviews and videos are very helpful.


2007 Honda Ridgeline

This wiring harness works great. I read where a faulty
wiring harness could be the cause of my Honda Ridgeline
blowing blinker fuses. I changed it and its working great.
I was concerned about the instillation but I watched a video
on it and it was quite simple.

Honda Ridgeline

While I haven't installed this harness on my Ridgeline yet I fore see no problems thanks to the video on e-trailer site. What impressed me the most was order placed 10:00am cdt on a Saturday and delivery on Mon. by 2:00 pm....unheard of speed!!!! You can be certain etrailer will be the first place I look for accessories for my truck.

Honda Ridgeline

I received my wiring harness on time and the installation was easy. The T connections fit my Honda Ridgeline exactly and the install video was very helpful. I would recommend this site and I will use it again.


Installation was pretty easy, only downfall was the adhesive on the back of the converter isn't very sticky. I had to use other adhesive to make it stick under my truck.


Easy transaction and fast shipment!!

2008 Honda Ridgeline

Harness fit perfectly. Instructions were clear and concise. I will definitely purchase from etrailer in the future.


We bought light harness and received it in excellent time. It was very easy to install.


Product arrived fast and was just what I ordered. Installation was easy, just plug it in and your ready too go. This was my second time using this company.

2006 Honda Ridgeline

Went together perfectly. The video showing the installation was a big help. Very satisfied with the quality of the product.


Working perfectly


Great product! Easier to install than expected. Only took me about 10 min to install and that included strapping the excess wire up and out of the way.

2007 Honda Ridgeline

so far, no problems with this product. installations was easy.


Clean and easy to install.

Show More Reviews

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

  • Can Curt Wiring Harness Be Used on a 2012 Honda Ridgeline RT to Tow a Small Trailer
    As long as the small utility trailer you plan on towing is wired correctly and does not have any shorts on the tail light circuitry you would have no problem installing Curt Custom Fit Vehicle Wiring part # C55585 on your 2012 Honda Ridgeline RT. Check out the installation instructions I attached for this product also.
    view full answer...
  • Recommended 4-Way Wiring Harness for a 2017 Honda Ridgeline
    I have a solution for your but when I spoke to my contact at Curt and he informed me that the 2017 Honda Ridgeline is a completely redesigned model from the 2014 to the 2017 and the # C55585 will not work. While there currently is no custom wiring harness for the 2017 Honda Ridgeline, a great universal option, I recommend for you to install the ZCI wiring harness # 119250KIT. The ZCI harness will install a 4-way trailer connector on your vehicle without cutting or splicing into your wiring....
    view full answer...
  • Parts Needed to Add 7-Way RV-Style Trailer Socket with 12V Power to 2014 Honda Ridgeline
    The 4-pole flat trailer wiring harness you referenced, part # 118400, does not fit your 2014 Ridgeline. It fits only earlier model years. And please note that this 4-pole wiring format carries only basic lighting signals - stop, turn and tail - but does not include a provision for 12V auxiliary power for maintaining the charge on a trailer-mounted battery, nor for any other functions. A similar 4-pole kit that does fit your 2014 Ridgeline (without the factory tow package) is part # C55585...
    view full answer...
    Image 1 for
  • Trailer Wiring Recommendation for a 2008 Honda Ridgeline for a 4 and 7-way and Brake Controller
    Yes, you will need a couple different wiring kits, but there is a way for you get both a 4 and 7-way on your 2008 Honda Ridgeline and have them both be fully functional so that you can install a brake controller. First, you will need the Curt Wiring Harness part # C55585 that you referenced to install a 4-way on your vehicle. Once that is installed you will be ready to install the Brake Controller and 7-Way Installation Kit part # ETBC7 that will give you a fully functional 7-way to use...
    view full answer...
  • Can a Brake Controller Install Port on a Honda Ridgeline be Used with ETBC7 Install Kit
    If you have the brake controller on your 2008 Honda Ridgeline but are using the hardwire kit # ETBC7 you could test the pins of the port on your vehicle to see if the 12 volt circuit is active with a circuit tester like part # PTW2993. If you find a pin with 12 volts all the time then you can use it for the black wire of the controller. Otherwise you will need to run the wire to the battery. For the red wire of the controller you can test other pins on the connector you found to see if...
    view full answer...
  • Trailer Brake Controller installation in 2010 Honda Ridgeline Without Factory 7-Way
    Your 2010 Honda Ridgeline will have an under-dash connection port for a trailer brake controller like the Prodigy P3 # 90195 only if it came from the factory with the 7-way trailer connector. Adding this connector using kit # 118253 does not provide the brake controller port. This part is intended as a factory replacement but not a retro-fit. For any vehicle that does not have the factory-installed 7-way and the under-dash port a brake controller installation will be hardwired. This process...
    view full answer...
  • Trailer Wiring Harness Recommendation for a 2008 Honda Ridgeline
    Yes, the CURT T-Connector Vehicle Wiring Harness with 4 Pole Trailer Connector # C55585 is the correct wiring harness for your 2008 Honda Ridgeline. To install this kit you will basically just need to access the tail light harness on both sides of the rear of your vehicle and install the harness from the # C55585 inline with it. Check out the installation instructions I attached that detail this also. If you need a 4 to 7-way adapter for a trailer that does not have electric brakes you...
    view full answer...
  • Wiring 2008 Honda Ridgeline to Power Reverse Lock-Out Solenoid on Hydraulic Trailer Coupler
    From your previous question, it looks like your trailer uses a 7-way connector, is that correct? If this is the case, you would begin by installing the # C55585 wiring harness you mentioned. You would then use a 4-pole to 7-way adapter, part # 37185. This adapter would simply plug into the 4-pole you installed, and will have 4 additional wires that might need to be connected according to your needs. The white wire with the ring terminal would need to be grounded to the trailer frame....
    view full answer...
  • Honda Ridgeline 2014 7-Way and Brake Controller Recommendation
    For your 2014 Honda Ridgeline the # C55585 is the correct 4-way for your vehicle. To convert the 4-way to a 7-way for just trailer lighting functions the # 30717 and the # 18138 would work well. If your trailer has brakes that need to be activated you would instead want the # ETBC7 for converting the 4-way since it will make it fully functional. For a brake controller I would recommend the Prodigy P2 Brake Controller part # 90885. This is our best selling brake controller because of how...
    view full answer...
  • Easiest Way to Install 6-Way Trailer Connector on 2011 Honda Ridgeline
    The easiest way to install 6-way wiring on your 2011 Honda Ridgeline will be to start with a 7-way that's custom fit for your vehicle like the Tekonsha part # 118253 and then use a 7-way to 6-way adapter # HM47570 to match the 6-way on your trailer.
    view full answer...

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Info for this part was:

Employee Joe V
Test Fit:
Joe V
Employee Mike L
Expert Research:
Mike L
Employee Jameson C
Expert Research:
Jameson C
Employee Andrew K
Video by:
Andrew K
Employee Lindsey S
Updated by:
Lindsey S
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Isabelle B
Updated by:
Isabelle B
Employee Dustin K
Video Edited:
Dustin K
Employee Cole B
Installed by:
Cole B

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