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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 # 55542
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Custom Fit Vehicle Wiring

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Custom Fit Vehicle Wiring 55542 - Custom Fit - 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 - no cutting, splicing or tapping required. Converter is made using SMT to ensure superior performance. 1-636-306-4830 to order CURT custom fit vehicle wiring part number 55542 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 (186)
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  • Why etrailer?

CURT Custom Fit Vehicle Wiring - 55542

  • 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 in rear cargo area
    • 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 interior trim panels 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 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.

55542 CURT T-Connector - Surface Mount Technology - 4 Wire

Installation Details 55542 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 - 55542

Average Customer Rating:  4.9 out of 5 stars   (186 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.


Put this on my 2010 Corolla (5 speed manual) for a bike rack and to tow a small motorcycle trailer.

Was easy to install by myself on this vehicle (has pre-drilled holes and don't have to drop the muffler).

Have done 2 300 mile-ish mountain towing runs with the motorcycle loaded up with no issues.

Would recommend!

Still no issues. Solid hitch
Ryan - 12/01/2020


No splicing required. Just disconnect the existing wiring connector, plug in the connector from the trailer connector wiring harness and then plug in the existing connector to the new connector. Works perfectly and is very easy to work with.


This wire loom really simplifies wiring up a trailer connection. Super simple to install and makes a trustworthy connection without splicing into the cars taillight loom. Took me longer to unclip the small factory clips than it took to install this kit. Save yourself money and frustration and buy this kit!


Took less then 15 minutes to install and hit the road. No foolish wiring under the vehicle to the battery.


Excellent products and service. Prices are great.
I highly recommend this company.


Very easy to install, easy to follow video instructions to follow; would absolutely buy again.

Works flawlessly a year later definitely recommend
Qtownpenn - 01/23/2022


Best pricing out there, Hitch received faster then expected, well packed. website has great information on installation.


It is simple enough that I can install it in minutes without slicing and cutting wires. In my case it would be the slicing of the wrong wires, pulling out the whole thing and many trips to the auto parts store without this part. For more skilled installers you can skip this product, but most likely will have to go to auto store for more parts, cut your finger while slicing wires and end up learning new words that cannot be said around children.


Very good product,the bolts were a bit difficult to install but that's ok


Very simple straight forward installation on 2000 F150 regular bed. Works great and was as simple as unplugging 1 connector and connecting the new adapter.

2011 Toyota Corolla

the wiring harness for my 2011 Corolla, fit perfectly, literally took me less that 10 minutes to install and deliver was fast! thank you !


Great easy plug in play. Hardest part is disassembling the trunk. Neg: Double sided tape doesn’t stick to device or auto… but no big deal.


The wiring harness worked perfectly! Thanks again!!!

2010 Toyota Corolla

I seem to have intermittent connection issues with the plug in tom the trailer , May be more trailer related but can't say it isn't the harness.

When theres an intermittent trailer lamp problem, most of the time it can be traced to a ground problem. Make sure the wiring harness is correctly installed on the vehicle, according to the installation instructions. Make sure the connectors are pushed together until they click. On the trailer, be sure that the ground connection to the trailer frame usually made on the trailer tongue is secure and not corroded. Make sure each lamp is grounded either by its mounting hardware being in direct contact with the trailer fame or by its ground wire being connected to the trailer frame. Ill link you to some help articles that will assist in your troubleshooting.
-- Etrailer Expert Mike L - 02/18/2019


Thank you ! What a great set up for my Toyota Corolla . Also I must say that customer service was very professional!!! I look forward to doing more business in the near future. Thank you and happy new year !

2006 Toyota Corolla

I can't claim all the credit for adding it. I did get a little help from my mechanic. I had some issues installing the hitch itself and needed his expertise to tap out the holes to mount it. When he did that he also connected the wiring harness, however it went easy and everything works fine now! Thanks

still working fine!
Raymond - 06/01/2019

2007 Toyota Corolla

Installed the Curt Wiring Harness on my Toyota Corolla and it fit and worked perfectly. Very simple installation- plug and play.

Great service from etrailer- highly recommend them as well- fast delivery.

After being used numerous times over the past year, the wiring harness is still working trouble free. Couldnt be happier with this product.
Anthony S - 04/24/2018


Great plug n play harness, I've had it on my vehicle for over a year and have had zero issues with it. Very easy to install as well.


This product design is great. I wish all trailer wiring installs were this easy. I'm an auto mechanic but it doesn't take an auto mechanic to do this. I used the web sight to order, no problems there. Product arrived in time estimated, undamaged and as expected. this might be my 30th purchase with etrailer and very pleased with them.


The video really made installing this item easy.


I ordered this rush shipping when my old harness (never tested that one, truly) wasnt working, and Uhaul had marked it up to corrosion. etrailer came through on rush delivery.

Sadly, my issue persisted with a new harness. My vehicle lights all work and worked perfectly, and I even tried reversing the harness left to right.

The harness does not turn on my running lights. When I hit brakes, I can get running lights. Turns/hazards dont work. I gave up. Same trailer or lighted carrier used on other vehicles and worked perfectly. Maybe something was done differently with my car at the factory. In the end we chose to only use the hitch carrier in the daylight on the corolla, and made sure all vehicle lights were visible around the cargo.

Vehicle is a 2006 Toyota Corolla CE, stick shift.


I like being able to just plug it into the existing hardward and not trying to figure out what wire to splice it with.

2005 Toyota Corolla

this is a very good product allows you to attach the trailer wiring without cutting your vehicles wiring . it sounds like a minor detail but it is not .it is always best to protect the integrity of your vehicles wiring . very happy with the product and the people at e trailer

the trailer hitch and wiring are both working well for us after about a years use . after having this thing for awhile i find it is just what i needed . i like the fact that when it is not being used the wiring goes in the trunk out of the weather .
mark s - 03/12/2017


This wiring was easy to install. Printed instructions were clear and the video on your website was very helpful.

Thank you.

This wiring is working well. We have used it many times during the past year.
Skip P - 09/07/2018

2008 Toyota Corolla

Perfect fit, quality hardware, excellent price, simple install.
Took 45 minutes to install the wiring harness & trailer hitch - piece of cake.

No locating and cutting wires - remove (2) electrical connectors and snap in the connectors on the wiring harness, put in a few wire ties to make it neat, clean, and professional looking, reinstall the panels, and done.

The only glitch was the instructions called for connecting a grounding wire which was not a part of the wiring harness and also not necessary.

Highly recommended! Probably saved ~ $150 versus getting it done elsewhere.

Show More Reviews

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

  • Trailer Wiring Harness Recommendation for a 2010 Toyota Corolla Towing Trailer with LED Tail Lights
    Yes, the Curt Custom Fit Vehicle Wiring # 55542 that you referenced would work on your 2010 Toyota Corolla and work well with the LED tail lights of your trailer. LED tail lights draw considerably less than incandescent bulbs so they should work well with the # 55542 since this harness has a 3 amp per circuit limit for the stop/turn lights and 7.5 amp limit per circuit for the running light circuit. I attached installation instructions and an install video for this product also.
    view full answer...
  • Solution for Trailer Wiring of 2007 Toyota Corolla Where Left Turn Signal Stopped Working
    If power is going into the converter box but none is coming out of it that would indicate that the convert is bad and need to be replaced. Since we don't have just the boxes by themselves available you'd want the new kit with part # 55542 which is the entire kit.
    view full answer...
  • Does Trailer Wiring for 2009 Toyota Corolla Need to be Grounded
    The Curt trailer wiring harness part # 55542 that you have does have instructions that say to ground a white wire yet the harness does not have a white wire to ground. That step is in there by mistake and you would be fine to ignore it.
    view full answer...
  • Troubleshooting Both Trailer Turn Signals Coming On With Right Blinker
    Sounds like you have some of your trailer wires shorted out to each other. You will need to go over the wiring of the connector on your tow vehicle and trailer to find the short between the two and fix as needed. I attached a couple help articles on troubleshooting trailer wiring for you to check out as well. You can also try improving the grounds of the lights to see if that helps too. Sometimes insufficient grounds cause all sorts of weird behavior.
    view full answer...
  • Turn signals not working with T-One Vehicle Wiring Harness, Part # 118387, on a 2007 Toyota Corolla
    From what you are telling me about your green wire being only half as bright as your yellow wire, most likely you have a weak ground. A weak ground can make some, but not all of the lights work properly. To fix this, the ground wire on both the trailer and tow vehicle should be secured tightly to a clean surface on the frame. A wire attached to the body or a surface with undercoating or rust can cause a ground problem, so check to make sure the surface you secure it to is bare metal with...
    view full answer...
  • Trailer Wiring Harness Recommendation for a 2010 Toyota Corolla Sedan
    The T-One Vehicle Wiring Harness with 4 Pole Trailer Connector, # 118459, is a powered converter that requires a direct connection to the vehicle battery. This virtually eliminates the power draw from the vehicle tail light wiring which protects the sensitive circuitry. The Curt T-Connector, # 55542, does not require a direct connection to the battery but the power draw from the trailer comes directly from the tail light wiring. For your 2010 Toyota Corolla, I recommend going the safer...
    view full answer...
  • When headlights are on, Left Turn Signal Does Not Work After Wiring a 2006 Toyota Corolla
    It sounds like you have a bad ground connection. You are correct that the # 55542 harness uses the vehicle ground, so I would turn my attention to the trailer. If all ground connections are not making good contact to bare metal, when the tail lights are turned on then the trailer lights will go out or not function properly. You will need to check all of the ground connections especially where the tail lights are mounted to the trailer frame, and where the light brackets are mounted if...
    view full answer...
  • Will Curt T-Connector Wiring Harness # 55542 Fit a 2011 Toyota Corolla
    The Curt T-Connector Wiring Harness, part # 55542 will fit your 2011 Toyota Corolla. This wiring harness will plug into the factory connectors located behind the tail lights. I also offer the Tow Ready T-One Wiring Harness, part # 118459 for your 2011 Toyota Corolla. This wiring harness also connects to the connectors on the tail lights, but it also includes a powered converter that requires a direct connection to the vehicles battery. This will eliminate the power draw from the vehicles...
    view full answer...
  • Difference Between the Tow Ready Harness and the Curt Harness for a 2009 Toyota Corolla
    The reason a wire is run to the battery on the Tow Ready Harness # 118459 is to help protect the tail light circuitry of your 2009 Toyota Corolla. You see, the # 118459 uses the tail light circuitry of the vehicle merely as signal wires and powers the tail lights of your trailer with the power it gets from the battery. Tail light circuits can be damaged if they are overdrawn and the # 118459 eliminates this problem by bypassing the tail light circuits as power sources. The Curt T-Connector...
    view full answer...
  • What Does Power Grip Marine-Style Power Cord Adapter # CAM55542 Weigh
    The Power Grip Marine-Style Power Cord Adapter # CAM55542 that you referenced weighs 19 lbs.
    view full answer...
  • Will TowReady Trailer Wiring Harness # 118459 Fit 2004 Toyota Corolla
    The TowReady powered wiring harness # 118459 is designed for the 2009 through 2013 model years of the Toyota Corolla. For your 2004 Corolla the recommended harness is Curt # 55542. This kit is simpler to install and actually will deliver higher rated current output than the Tow Ready kit. Your Corolla has heavier wiring than later model years and so can use the non-powered Curt harness. However, my contact at Tow Ready did confirm that you could use kit # 118459 on your 2004 Corolla...
    view full answer...
  • 25 Foot 50 Amp To 50 Amp RV Power Cable Suggestion
    The closest power cord we carry is the Power Grip Marine-Style Power Cord Adapter w/ Handle # CAM55542. This cable is 50 amp to 50 amp, 25' long, and features a built-in handle for easy removal.
    view full answer...
  • Hidden Hitch Recommendations for a 2013 Toyota Prius V and a 2004 Toyota Corolla
    The Trailer Hitch # 24847 is confirmed to fit your 2013 Toyota Prius V. This is a 1-1/4 inch hitch, and you are correct, there is only 1-1/4 inch hitch available for this vehicle. At this time we do not have any wiring options for this vehicle. You may have to contact a Toyota dealership to find this. For your 2004 Toyota Corolla you would want the Draw-Tite part # 24913. I attached installation instructions and an install video for this product for you to check out also. There is wiring...
    view full answer...
  • Trailer Hitch & Wiring Harness Fits on 2006 & 2011 Toyota Corollas
    Yes, the 1-1/4-inch Class I trailer hitches that fit your 2005 Toyota Corolla will also fit the 2011 model year of that same vehicle. The three hitches we offer for both cars are shown on the linked page, including Draw-Tite # 24913 Please note that you must use new hardware to re-install the hitch in the new vehicle. We offer part # RHK which includes all of the required hardware components. Just enter RHK into our search box and click go. Then click on the item RHK and enter your hitch...
    view full answer...
  • Are Class II Hitches Available for a 2007 Toyota Corolla?
    Each hitch that is available for a 2007 Toyota Corolla is a Class I hitch with a 1-1/4" receiver such as the Draw-Tite # 24913. According to the '07 Corolla's owners manual, the towing capacity of the vehicle is 1,500 lbs, which is why there are no Class II hitches available. The Class I Draw-Tite has a 2,000 lbs towing capacity and 200 lbs tongue weight capacity, and if you were looking to tow, you would need to add a 4-flat connector # 55542 as well as drawbar # 3593, which comes with...
    view full answer...
  • Troubleshooting Curt 4-Pole Wiring Harness 55542 on 2009 Toyota Corolla
    Thank you for purchasing the Curt trailer wiring harness # 55542 and for sharing the detailed troubleshooting steps you have already taken to find the issue with the passenger-side trailer lights. It sounds like you have had a friend connect his vehicle to your trailer and noted that the trailer lights all worked fine with his vehicle and wiring. Based on this it sounds like the problem is with the harness-to-vehicle connection point on the passenger side. Disconnect the passenger side...
    view full answer...
  • Vehicle Wiring Harness For A 2004 Toyota Corolla
    We do have a plug and play kit that is confirmed to fit your 2004 Toyota Corolla. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 55542 will plug into your vehicle's wiring harness, which is located behind the driver's-side and passenger's-side interior trim panels in your rear cargo area. It is recommended that you use a small amount of grease # 11755 on all electrical connections including the 4-pole connector itself. This will help prevent corrosion....
    view full answer...
  • Can I Install the Hitch from My 1997 Toyota Corolla onto my 2004 Carolla
    To put a hitch on your 2004 Toyota Corolla Sedan you would need a Draw-Tite Trailer Hitch for the Toyota Corolla, 2004, part # 24913. If your newer Corolla was from the years 1993-2002 you could reuse the hitch from your 1997 Corolla, but the 2004 has a differently designed frame from your 1997 that would not allow you to install the hitch onto your 2004. Here are some other items you may need to complete your towing setup: Curt Custom Fit Vehicle Wiring for the Toyota Corolla, 2004,...
    view full answer...
  • Receiver Hitch Recommendation for a 2008 Toyota Corolla LE
    You are correct, the Curt and Draw-Tite receiver hitches all look very similar and also offer the same weight capacities. The biggest difference between the two brands of receiver hitches for your 2008 Toyota Corolla is the fact that the Curt, # C11265, requires the use of stabilizing straps, # 18050, for all non-trailer loads like bike racks, cargo carriers and so forth. Failure to properly support these loads will void your hitch warranty from Curt. The Draw-Tite brand does not require...
    view full answer...
  • Need Trailer Wiring to Use on 2008 Toyota Corolla and Fold-Up Trailer Kit
    We have a custom fit vehicle wiring for your vehicle. I used the Fit Guide on the website and found that the wiring kit you need for your 2008 Toyota Corolla is the Curt Custom Fit Vehicle Wiring, part # 55542. This kit will wire into the vehicle wiring and allow you to connect your trailer to your 2009 Toyota Corolla. Yes, this custom fit wiring simply plugs into your factory wiring harness, it is a plug and play kit. When connecting the trailer wiring to your vehicle it is always a...
    view full answer...
  • Recommendation for Transporting Mobility Scooter with 2006 Toyota Corolla
    The easiest way to transport a mobility scooter with your 2006 Toyota Corolla is to use a small trailer with a ramp. We do not offer any hitch-mount cargo carriers with a ramp that will fit the Class I trailer hitch on the Corolla. To tow a trailer with the 2006 Corolla, you will want the recommended drawbar # 3593 for the Draw-Tite Class I Trailer Hitch # 24913. The # 3593 drawbar offers 2-1/8 inch rise or a 2-3/4 inch drop, and comes with the needed pin and clip. For a hitch ball with...
    view full answer...
  • Recommended Trailer Hitch Receiver And Wiring For 2007 Toyota Corolla CE
    The Draw-Tite Sportframe Trailer Hitch Receiver - Custom Fit - Class I - 1-1/4" # 24913 will fit all Toyota Corolla models from 2003-2017. It is a confirmed fit for your 2007 Toyota Corolla CE. If you will be using this hitch for towing, I recommend the compatible ball mount # 3593 and a hitch ball like # 19256 for a 1-7/8 inch option or # 19258 for a 2 inch diameter ball. For wiring, I recommend the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 55542...
    view full answer...
  • Hitch Recommendation for a 2012 Toyota Corolla S
    I checked with Curt and the Curt Hitch part # C11265 that you referenced is confirmed to fit all model 2012 Toyota Corollas so it would work on your S model. I attached an install video for you to check out as well. For trailer wiring you would want the Curt Wiring Harness part # 55542, ball mount # C45521, 1-7/8 inch ball part # 19256, 2 inch ball part # 19258.
    view full answer...
  • Bolt Size to Install a Trailer Hitch on a 2004 Toyota Corolla
    The weldnuts in the frame for your 2004 Toyota Corolla to install a trailer hitch are M12 nuts. The bolts used to install a hitch, # C11265 as an example, are M12-1.25 x 30mm grade 5. It is recommended to clean out the weldnuts prior to installing the hitch. Road grime and corrosion can get compacted in the threads and you would not be able to thread in the bolts without first cleaning the weldnuts. I have included some links to the right that should help. If you plan on doing some towing...
    view full answer...

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Info for this part was:

Employee Mike L
Expert Research:
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Robert G
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Employee Adam R
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Updated by:
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