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 # C55378

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Custom Fit Vehicle Wiring

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Custom Fit Vehicle Wiring C55378 - Custom Fit - Curt
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In Use/Installed


  • Custom Fit
  • Trailer Hitch Wiring
  • Curt
  • 4 Flat
  • Powered Converter
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. Call 800-298-8924 to order Curt custom fit vehicle wiring part number C55378 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.


  • All Info
  • Reviews (38)
  • Q & A (5)
  • Videos (3)
  • Photos
  • Why etrailer?

Curt Custom Fit Vehicle Wiring - C55378

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.


Features:

  • 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 point behind rear bumper
    • Plug in connector
    • Plug in fuse holder under hood
  • 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


Specs:

  • Maximum amperage:
    • Stop/turn lights: 3 amps per circuit
    • Tail lights: 6 amps per circuit
  • Limited 1-year warranty


Installation

This custom-fit T-connector plugs into your vehicle's wiring harness, which is located behind the rear bumper, along the passenger's-side frame rail. Once you've plugged in the T-connector, locate the truck's power wire on the driver's side of the engine compartment and plug the included fuse holder into the matching connector on the power wire. Then attach the fuse holder to the positive terminal on the truck's battery.


Once installation is complete, the 4-way connector will be stowed beneath your vehicle, near the trailer hitch. A mounting bracket (sold separately) is recommended to keep the connector secure.


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.



55378 CURT T-Connector - Surface Mount Technology - 4 Wire



C55378 Installation InstructionsInstallation Details C55378 Installation instructions

This Product Fits The Following Vehicles

2001 - 2002 Toyota Tundra

2000 - 2002 Toyota Tundra excluding factory towable bumper

2001 - 2002 Toyota Tundra with factory towable bumper



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 Trailer Wiring Harness Installation - 2001 Toyota Tundra

Today on our 2001 Toy0ta Tundra, we'll be installing the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector, part number C55378. We'll begin here underneath the rear of the vehicle, over here on the drivers side. You'll see that there's a large gray plug right here that actually has an end cap in it. To unplug this, we'll simply push in on the locking tab and gently pull downward. This is the wiring that we'll be tying in the new Curt T-Connector wiring harness to. Now for the box and the 4-flat end of the wiring harness, we're going to route it up here through the frame. This will allow us to protect the box, as well as give us a good flat area to secure the box using the 2-sided tape. We'll go ahead and use a little bit of rubbing alcohol to clean the surface first, before we attach the 2-sided tape to the box, and then attach the box to the frame of the vehicle. We'll go ahead and plug in our connection from the new wiring harness to the factory wiring harness, making sure that we hear the locking tab click into place. We'll go ahead and use a few zip-ties to secure up any excess wiring. Now for the 4-flat, we'll route it down here to the center of the hitch area. We'll then take the cover for the 4-flat, put it on the end of the 4-flat, and then loop it through the safety chain hole on the hitch. Once that goes through, we'll take the end cap and put it back over the end of our 4-flat.

This will keep any dirt and debris out of the 4-flat when not in use, as well as securing it to the hitch. Now we need to move up to underneath the hood where we'll take the other piece of wiring harness. The one that has a fuse holder in it will need to be tied in with the battery. We're going to go ahead and loosen up the bracket that holds the battery in place so we can slide it over enough to give us a little more working room to gain access to the factory plug. Again, this plug has a cap built into it already to protect it from dirt and debris. We'll simply push in on the locking tab and remove the dust cap. We'll then take the end of our new wiring harness and simply plug it into it, again, making sure that the locking tab clicks into place so that the connection is secure. We'll then need to route the other end with the ring terminal up to the positive side of the battery. We'll go ahead and loosen up the nut on the positive side of the battery and add the ring terminal on the wiring harness in-line.

We'll then tighten the nut back down. Now that that's done, we can go ahead and put our battery clamp back down, holding the battery back in place. Next we'll need to install the 10 amp fuse that comes with the kit in the fuse holder. We'll then put the cap on the fuse holder. We'll also use a few zip-ties to help secure any excess wiring up here. All that's left to do is to to run through and make sure that our new 4-flat wiring is working properly,so we'll take our test light here at the rear of the vehicle. We'll take the ground on the test light and touch the open prong on the 4-flat, which is the white wire, and we'll have someone run through the light functions. We'll touch the brown wire for the running lights, the yellow wire for the left turn, the green wire for the right turn, and the yellow or the green wire for the brake signal. As you can see here, everything is working just fine. With that, that will conclude our installation of the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector, part number C55378, on our 2001 Toy0ta Tundra.

.


Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C55378

Average Customer Rating:  5.0 out of 5 stars   (38 Customer Reviews)

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.

- C55378
by:
2002 Toyota Tundra

I received the wiring adapter very quickly after I placed my order. I had already watched the video etrailer.com, that was specific to my 2002 Toyota Tundra, so the install was straight forward and simple. My truck had a 4 pin connector spliced in by the previous owner but the brake lights didn’t work on my trailer. I installed the adapter kit and everything works as it should now. I’m super impressed with the products, the communication, and the info provided by etrailer. Etrailer.com is top notch, thank you! 555737



- C55378
by:
2002 Toyota Tundra

Making electrical connections on a car, truck or other vehicle can, at times, be a challenge. The C55378 wiring kit for my 2002 Tundra was a breeze to install. The instructions are very clear and the video on the eTrailer web site made installation that much easier. Not sure about the converter electronics but the turn signal draw on the blinker controller didn't make the blinker indicator operate at warp speed and burn the controller out! All the necessary cable ties and adhesive pad are included in the kit; nothing else to buy or add; other than your trailer! Once again, the folks at eTrailer are great communicators and kept me advised of the product whereabouts through the entire order process. 541615



- C55378
by:

Work good. Old unit was bad and needed replacing. This one did the thing. Old one was a different brand that I got someplace else. Everything is running smooth. 657017



- C55378
by:

Excellent perfect fit installed in lass than 30 minutes. 656340



- C55378
by:

Product was simple to install. Works flawlessly. Hooking into the factory harness makes the entire process extremely easy. If you know how to use a flat head screwdriver and a ratchet you can install this with ease. 652969



- C55378
by:

Product was delivered quickly after order with easy to follow instructions just plug and play . I would recommend this product to a friend 652593



- C55378
by:

perfect 646427



- C55378
by:

works ok , but need a reminder to double check plug ins before closing up ones work as the new pins will push backwards and not connect then after one closes up he will find a light not blinking properly , did go back and take car apart and find the pins that didnt connect properly , then all worked , thanks , david 616863



- C55378
by:
2002 Toyota Tundra

Product exactly what I needed. Came fast, easy install. 529227



- C55378
by:
2001 Toyota Tundra

You guys are geniuses, I order a trailer wiring kit c55378 installation was quick and easy. It was plug and play. I was amazed thank you. 528489



- C55378
by:
2002 Toyota Tundra

I bought this device to replace a failed unit from another manufacturer. I haven't had any problems with the new device and expect it to last longer since it's solid state. 527053



- C55378
by:
2001 Toyota Tundra

The wiring harness was very easy to install and I used the online videos that were very helpful. 526226



- C55378
by:
2001 Toyota Tundra

Fast shipping and easy installation. Thanks etrailer. 519933


Comments

No problems whatsoever. Still works like new.

Michael D - 06/09/2019

56377

- C55378
by:
2001 Toyota Tundra

Super happy with service and product quality of the trailer wiring harness adapter I ordered. Straight forward and simple 10 min installation. The instructions were a little off as far as location of factory harness to plug into, but that's not a difficult thing to figure out on your own. Will use etrailer whenever they have what I need. 515229



- C55378
by:
2002 Toyota Tundra

Product came in a very fast manner was also easy to install great product I highly recommend it to anybody who tries it 510845



- C55378
by:
2002 Toyota Tundra

Product arrived in time stated, all items included. easy to install with the instructions provided. Is pretty much plug and play. 502026



- C55378
by:
2002 Toyota Tundra

Very fast shipping. Direct fit less than 10mins to install.. 486451



- C55378
by:
2015 Toyota Tundra

The wire harness for my trailer went out on my 2001 Tundra. After checking with local businesses, I discovered that it would cost about 150 dollars to get a harness installed. I decided to check the internet and found a video produced by etrailer. The video showed how easy it is to do the installation yourself. I ordered the harness that fits my truck, and the delivery was fast. Taking my time, I installed the harness in about 15 minutes and saved 100 dollars in labor. By the way, the new harness works as it should. I have purchased several products from etrailer and was pleased with every purchase. 444906


Comments

It has been one year since purchasing this wire harness. Am still very pleased. The harness works with zero problems.

John h - 10/22/2018

44920

- C55378
by:
2001 Toyota Tundra

Great product and service. Had it installed in about 45 minutes. Worked perfectly with my trailer first time. Thank you. 437504



- C55378
by:

plug an play easy install 407333



- C55378
by:

Easy install 406071



- C55378
by:
2001 Toyota Tundra

Easy install fit perfectly quick shippi ng 381348



- C55378
by:

It was great,had no problem installing . Had it on and working in about 45 min. Hook up to bass boat and gone fishing. 374865



- C55378
by:
2002 Toyota Tundra

The unit I needed was in stock. It was shipped within a few hours of my ordering it. The unit was well packaged. The service was excellent, I was back in service shortly after receiving it. 367455



- C55378
by:
2001 Toyota Tundra

Was just the product I had been searching for. 348412



- C55378
by:
2002 Toyota Tundra

Unlike other online dealers etrailer.com has a very well designed web site that is easy to navigate. What was really helpfully were the utube instructional videos. They made a Video for installation of the trailer wire harness for my 2002 Toyota Tundra. Impressive. 280777



- C55378
by:
2001 Toyota Tundra

Yes i got the shipment n it was in good shape thank you i lust didnt got it on yet but i will this weekend . 267133



- C55378
by:
2001 Toyota Tundra

Great service from beginning to end. 240035



- C55378
by:
2002 Toyota Tundra

The curt T-connector was an exact matched fit to my 2002 Tundra. The instruction videos on your web site were very good quality. You are now my go-to connection for trailer parts. Thanks. 237641



- C55378
by:
Toyota

exactly what was required. Toyota dealer parts dept. said item was discontinued, U-HAUL said it was a Toyota dealer item. Y'all had it 217812



- C55378
by:
2001 Toyota Tundra

Was very easy to hook up the wiring everything is working great absolutely recommend it 193272



- C55378
by:

The wiring kit arrived 2 days earlier than promised. It took me 10 minutes to install. No problems at all. 172037



- C55378
by:
2002 Toyota Tundra

This wiring kit was a great solution to my problem. I had old, corroded wring at the end of my 4-pole trailer connector. I found the etrailer videos very helpful in pointing me to how easy it can be to replace just the corroded peice. The parts were just the right parts, fit perfectly and took about 20-min to get the whole thing done. And the shipping at the normal rate was fast...ordered on a Sat PM and received on Tues. 144363



- C55378
by:
2002 Toyota Tundra

everything was as expected--received in good time and good shape--price was very competitive--thanks 136167



- C55378
by:
2001 Toyota Tundra

Good product, Easy To Install, Fast shi pping 97956



- C55378
by:
2002 Toyota Tundra

easy plug and play 77338



- C55378
by:
2002 Toyota Tundra

Excellent because I just installed it. Had a T-One I bought from ETrailer 10 years ago that finally went bad. ETrailer does an excellent job with selection and service. I chose the Curt model due to highter amps per circuit 9 as compared to 7.5. Towing something with a higher amps draw is the best way to destroy it and never use more than a 10 amp fuse!!! 69782



- C55378
by:

The hitch mounted on the chassis with no problems. Did the job in no time with the help of my son. I was doubtful but it was real easy. 66047


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Ask the Experts about this Curt Custom Fit Vehicle Wiring
Do you have a question about this Custom Fit Vehicle Wiring?


  • 4-Way Trailer Wiring Harness for a 2002 Toyota Tundra
  • Wiring harness # 18246 is not a confirmed fit for your 2002 Toyota Tundra but we do have wiring harnesses that will work. To add a 4-Way you can use # C55378, # 118378, or # HM43375. If it were me I would go with # 118378 because it is the best value and we hear about fewer problems with the Tekonsha brand. I have linked a video showing an example installation for you.
    view full answer...

  • Is the Curt Converter Box for a 2002 Toyota Tundra Replaceable
  • The converter box for the Curt T-Connector Vehicle Wiring Harness part # C55378 is not available as a separate replacement part unfortunately. However, I actually recommend you take a look at the T-One Vehicle Wiring Harness part # 118378 instead which we have found to be much more reliable. The issue that causes the converter boxes to fail is excessive movement. The above Curt converter box attaches using adhesive which is not always the best method. The Tekonsha converter box attaches...
    view full answer...

  • Does Curt T-Connector Vehicle Wiring Harness # C55378 work with LED lights
  • Yes, the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C55378 that you referenced would work well with LED lights on your vehicle or trailer lights. I attached an install video for this wiring harness for you to check out also.
    view full answer...

  • Troubleshooting Installation of Curt 4-Pole Wiring Harness C55378 in 2002 Toyota Tundra
  • The two wiring harness kits you referenced, Curt # C55378 and Tekonsha # 118378, are both correct fits for your 2002 Toyota Tundra. Both of these kits are multi-part harnesses that include the required fuse/fuse holder and the installation of the Curt kit in a 2002 Tundra is shown in the linked video. The troubleshooting steps I suggest are to double-check that all connectors have no bent or damaged contacts, that they are fully seated together and that the ring terminal on the harness...
    view full answer...

  • Does Curt Trailer Wiring Harness C55367 Fit 2001 Toyota Tundra
  • For your 2001 Toyota Tundra the correct Curt trailer wiring harness is the part # C55378 which is a confirmed fit. The part # C55367 only fits 2000 Tundras.
    view full answer...


Do you have a question about this Custom Fit Vehicle Wiring?




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Info for this part was:

Test Fit:
Joe V
Edited by:
Leah B
Video by:
Zack K
Written by:
Lindsey S
Video Edited:
Jeff D
Expert Research:
Jameson C
Video Edited:
Jacob T
Video Edited:
Dustin K
Photos by:
Jim W
Test Fit:
Shane T
Video by:
Alan C
Updated by:
Sarah W
Updated by:
Kristina F

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