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  1. Custom Fit Vehicle Wiring
  2. Tekonsha
  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 4 Flat
  6. Powered Converter
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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

Our Price: $60.34
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Custom Fit Vehicle Wiring

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T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector Powered Converter 118498
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Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered ModuLite reduces strain on wiring system. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number 118498 or order online at Free expert support on all Tekonsha products. Great prices and Fastest Shipping for T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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Tekonsha Custom Fit Vehicle Wiring

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • Powered Converter
  • Tekonsha

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered ModuLite reduces strain on wiring system.


  • 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
    • Locate connection points behind tail lights
    • Plug in T-connector
    • Run hot lead to car battery
  • Includes ModuLite 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 of 16-gauge bonded wire
  • Comes with dust cap for 4-way flat connector


  • Maximum amperage:
    • Stop/turn lights: 2.1 amps per circuit
    • Tail lights: 5.6 amps per circuit
  • 1-Year limited warranty


This custom-fit T-One 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.

T-One Connection Location Points Behind Tail Lights

Once you've plugged in the T-connector, run the hot lead up to your car battery. Connect the lead to the included fuse holder, and then connect the fuse holder to the positive terminal on your battery and insert the provided fuse.

Once installation is complete, the 4-way flat connector will be stowed within the jack storage compartment of your rear 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.

ModuLite Powered Tail Light Converter

A ModuLite power module is built into this T-One 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 your trailer. This power module functions as a tail light converter to combine 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.

With a ModuLite, your trailer's lights will be powered without overloading your vehicle's electrical system. Because the module draws power directly from your car's battery and bypasses the electrical routes that are used by a basic wiring harness, there is virtually no draw on your tail light circuits.

118498 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite

Item # 118498

Installation Details 118498 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Satisfaction Score:

Customer Reviews

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 118498

Average Customer Rating:  4.7 out of 5 stars   (215 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered ModuLite reduces strain on wiring system.


Wiring Harness works as it should and not too difficult to install.


One year later - absolutely no issues with the wiring harness. I followed all of the instructions and things went well. During the install I ran into an issue of the long wire that was going to the battery , was a bit short (despite following the directions ), but a short splice of a compatible wire has fixed the issue. No issues with connecting to my trailer harness. I have always added a touch of dielectric paste to keep the connections good and water out. Proper length - no issues with reaching. Works every time, no glitches. Very satisfied with this product.


The product worked well and was easy to install. However, the power wire that runs to the battery is about 6" too short. I was able to make it work, but barely. I nearly needed to extend it. If it were 6-12" longer it would have worked so much better.

However the instructions were easy to follow and I greatly appreciate the videos from eTrailer.


I installed this myself. Took me maybe two hours. Its been a while but I believe I found a youtube video for wiring my specific car and just followed the directions. It worked the first time I rented a trailer and still works now more than a year later.

2013 Toyota Sienna

Harness plugged right in, I had plenty of wire for the connection to the battery. I routed the trailer plug wire through the bumper support and slid it out the rear underbody panel.

2014 Toyota Sienna

This is a great product. The wiring was thick and didn't feel like a cheap Chinese product. I'm happy with this wiring harness. I installed it on my 2014 Toyota Sienna. Even though the instruction video is not updated for the 2014, the instructions it came with contained a picture of the shroud and where to cut, which was the only difference (shroud size, only one cut needed on the 2014) between the 2014 Siennas and the ones from prior years.

You'll see in the picture attached, I purchased the loom to protect the wire. I would recommend doing the same.

The only thing that would have made more sense to me is if the box attached to the drivers side since that is where the battery is. There would be a lot less wire to route under the vehicle. Other than that, it worked on my first try and I'm happy with that! :)

Kelly H.


Its been a year already? Wow! Since I dont have a truck, I use my minivan and aluminum trailer frequently. I have no regrets buying this wire harness and would buy again.


So far it has been just fine good quality hitch . so far i have only used it for a cargo carrier worked great .

2016 Toyota Sienna

Worked great for our 2016 Toyota Sienna SE -- straightforward install, especially if you've done anything like this before. E-trailer's video install demos make it a snap. A great value - happy to recommend it to others.


Plenty of heavy gauge wire to complete installation.


The wiring harness was very easy to install. The hardest part was running the power wire up to the battery but I was able to find a safe path along the frame. The rest of the unit tucked nicely in the spare tire area and the wires run under the carpet so it's not seen day to day.

2013 Toyota Sienna

The hitch is solid/sturdy. It was easy to install. I use it frequently and have only had one consistent problem. Once attached to my 2013 Toyota Sienna, ground clearance is only 7 inches. See picture. Add the weight of my boat, and that clearance drops to 3 inches. I realize that most of that blame is owned by Toyota, but still, there's at lease another inch or so that could have been gained through improved design of the hitch. I had to add an Air Lift 1000 to bring it back to 7 inches clearance.

2011 Toyota Sienna

Finally, someone who can provide a pig-tail for the 2011 Toyota Sienna. Thank You. Quick shipping too.

2015 Toyota Sienna

Horrible customer service! Next to comcast this is the most frustrating company I have ever had to deal with. They sent me the wrong part 2 times. I even contacted the manufacturer to confirm they were sending me the wrong part and etrailer still don’t seem to understand their error. I have communicated with no less than 8 different people and still don’t have the right part. I am sure they will want to charge me a classy “restocking fee” when I have been waiting on them for weeks. If anyone actually cared this would have been an easy fix. You are better off shopping elsewhere…

Etrailer Expert

Jenny N.


I am very sorry that we have not been able to provide the harness that will work for you. I wanted to let you know that there not would be a restocking fee charge for sending back the harness. You would receive a full credit for it.

2018 Toyota Sienna

Just received it by way of UPS. I'M so excited to do the install tomorrow!


Great product, easy to follow instructions and installation.

Dean P.


It worked great. plugged right into my vehicles wiring

2011 Toyota Sienna

The hitch fit perfectly, looks great on the van and the wire harness installed easily. One suggestion before installation is watch the videos here on and it makes your installation easier!


Super easy install on my 2012 Toyota Sienna Limited. I’ll always choose etrailer due to their customer service, videos, etc. Nice product.

2014 Toyota Sienna

Website relatively clear for selecting product. Video tutorials excellent. Order process easy and fast. Product shipped same day and delivered for free two days later. Product installed perfectly and is good quality product.


Quick delivery, great instructional videos, easy installation!


Great company with fast shipping and excellent products


It was just to essay to install having all then parts and instructions



so far, so good. Still working as the first day. Very happy


all the parts fit my toyota van. this will protect the electronics of the car.


received all item in good condition and packaging. All items fit well and relatively easy to install. Very satisfied.

2012 Toyota Sienna

Its been great, already a year past and still working great.


This plug and play kit is a BREEZE to install. So easy I did it while fairly inebriated (didn't drive to test it though). Since my boat trailer has LEDs, I spliced into the 10A/120W cigarette lighter socket that was close by the passenger tail light instead of running all of the way up to the battery. You'll need two Orange Cap wire nuts to do it my way and it only works in accessory mode instead of all of the time, but super easy. Entire kit except power supply was literally plug and play. Thank you etrailer for your responsive order process from section to review.

Show More Reviews

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

  • Can the T-One Vehicle Wiring Harness Draw Power from a Cargo Light on a 2012 Toyota Sienna
    The 12 volt power wire with the T-One Vehicle Wiring Harness part # 118498 must be run to the battery while installed on your 2012 Toyota Sienna. It cannot be powered from any other existing circuit on the vehicle such as a cargo light because this would likely exceed the circuits amperage draw rating. It would also void the warranty of the wiring harness which is one year. If you need help routing the 12 volt power wire to the battery I have attached a help article on how to do so as well...
    view full answer...
  • Does Tekonsha Trailer Wiring Harness for 2013 Toyota Sienna Come with Everything Needed to Install
    The T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118498 that you referenced comes with everything you'll need to install it. No additional items would need be needed to install. I attached an install video for this kit on a 2013 Toyota Sienna just like yours as well.
    view full answer...
  • Why is Trailer Wiring that Draws from Vehicle Battery Better than Non-Powered Kit
    The benefit to a non-powered trailer wiring harness is that it's a bit easier to install since you don't have to run a wire up to the battery of the vehicle. The advantage to a powered kit is that it does a better job protecting the taillight circuits of your vehicle. Instead of drawing power for the trailer taillights from the vehicle taillights it only uses the vehicle taillights as signals and then draws all the power for the trailer taillights from the vehicle battery. In the long run...
    view full answer...
  • Does Tekonsha 118498 Fit 2013 Toyota Sienna SE
    Long story short...the Tekonsha trailer wiring kit part # 118498 is a confirmed fit for your 2013 Toyota Sienna SE. It was only after 2015 did the wiring manufacturers have to come up with separate kits for the SE models and the non-SE models. I attached an install video for this wiring harness on a similar 2014 Toyota Sienna for you to check out as well.
    view full answer...
  • How a Tow Ready Custom Fit Vehicle Wiring, part # 118498, Connects to 2011 Toyota Sienna
    When installing this Tow Ready Custom Fit Vehicle Wiring for the Toyota Sienna, 2011 part # 118498 on 2011 Toyota Sienna you are actually using your vehicles current tail light circuitry that is located at the rear of your vehicle. It sounds like your salesman was trying to explain to you that your Toyota Sienna will not be wired from the factory for trailer wiring, but if you install this custom wiring kit for your Sienna you will be good to go. Make sure you use the included inline...
    view full answer...
  • Does the T1 Trailer Wiring Harness # 118498 Have to be Connected Directly to the Battery
    The T1 trailer connector, # 118489, was only tested when connected to the positive terminal of the battery. Connecting it anywhere else can void the warranty of the harness. There are other problems that could occur since the 12 volt power supply was not designed to power trailer lights. If there was a short in the trailer wiring, that could damage the electrical system of the vehicle. Having it connected to the battery isolates the vehicles sensitive electronics. I have included a link...
    view full answer...
  • Does Power Wire of Tekonsha Trailer Wiring 118498 Have to be Connected to Function
    Not all vehicles can handle the additional amperage draw of the trailer taillights on the vehicle taillight circuits. Those vehicles need setup that draws power from the battery. Some vehicles have higher rated circuits that can handle this, and others need to have the power drawn straight from the battery to protect the taillight circuits. If you do not connect the power wire to the vehicle battery the trailer wiring harness # 118498 would not function at all.
    view full answer...
  • Compatibility of Tow Ready T-1 Connector Part # 118498 for 2011 Sienna with LED Trailer Lamps
    The Tow Ready T-1 Connector with Modulite, part # 118498 is compatible with LED trailer lights. The LED lamps draw much less current than incandescent lamps, so you should have no worries. I will link you to the installation instructions, so that you can look them over.
    view full answer...
  • Low Voltage Into Converter Box of T-One Wiring Harness 118498
    Thanks for all that info and since you are getting low voltage going into the converter box of the T-One Wiring Harness # 118498, my best guess is a finicky ground. If you grounded it via an existing screw, that needs to be connected to a clean metal surface - including no paint. If you did that ground methold I would also try using a new ground with the self-tapping screw provided instead of an existing screw, as that may help. I have also added a link below to a help article on 4-way...
    view full answer...
  • Why Does 4-Pole Wiring Harness Need Direct Battery Power Connection
    You do need to make a direct wired battery connection for a powered wiring harness like # 118498 because the small accessory 12V convenience outlets provided in vehicle do not have a high enough current rating to power the harness and all of the trailer lights. These handy outlets are great for things like charging a cell phone but they can't deliver the current needed to power trailer lights. The other concern is that were the plug-in connection to that outlet to come loose you would...
    view full answer...
    Image 1 for
  • Install Video Guide for Routing Power Wire of Tekonsha Trailer Wiring Harness on 2014 Toyota Sienna
    We've only ever installed the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118498 underneath the bottom of the vehicle since that's what the install instructions recommend. I attached an install video that would walk you through that entire process which really isn't too bad. It more or less comes down to just avoiding moving parts and hot components. I am sure running the wiring through the interior is possible but we don't have a way to really recommend that.
    view full answer...
  • Installation of Curt Wiring Harness # 56146KIT in 2013 Toyota Sienna
    Thank you for your recent purchase of hitch receiver and wiring harness from etrailer. The Curt Wiring Harness # 56146KIT is a correct fit for your 2013 Sienna. Thank you for submitting your two photos. This trailer wiring harness installs primarily at your Sienna's tail light assemblies and one additional connection for +12V power is made to the vehicle battery through the included fuse holder. I cannot tell from your first image exactly where on the vehicle you found those connectors....
    view full answer...
    Image 1 for
  • Best Trailer Wiring Harness Recommendation for 2011 Toyota Sienna Limited
    The Tekonsha trailer wiring harness part # 118498 is the best trailer wiring harness for your 2011 Toyota Sienna Limited. This fits the SE and non-SE models as well as the Limited model like you have. I attached an install video for this for you to check out on a similar 2011 Toyota Sienna as well.
    view full answer...
  • Vehicle Wiring Harness Recommendation for 2015 Toyota Sienna SE AWD
    The trailer wiring harness I recommend for your 2015 Toyota Sienna SE AWD is the Tow Ready T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118498. This wiring harness installs in line with your vehicle's factory wiring behind the vehicle taillights. You will not need to cut or splice into the factory wiring to install this wiring harness, simply unplug the factory wiring from the taillight and plug the wiring harness in between. The # 118498 also features a powered ModuLite...
    view full answer...
  • Parts Needed to Install 7-Way and 4-Way on 2013 Toyota Sienna
    We have just what you'll need. You will need to start with a 4-way confirmed as a fit for your 2013 Toyota Sienna like the T-One kit part # 118498. Then to convert it to a 7-way and still allow you a 4-way connection all you'd need is the part # 37185. The 4-way of the T-one would simply plug in to this and you'd a 7-way connection with a 4-way connector available as well. I attached an install video for the 4-way for you to check out as well.
    view full answer...
  • Options for Accessing the Battery for Wiring a Tow Ready Wiring # 118498 on a 2011 Toyota Sienna
    You have a couple options at this point. You can either find a way to route the wire through the firewall either by finding a hole in the firewall or drilling a hole in the firewall, or you can route the wire out through one of the drain plugs in the floorboards of vehicle Sometimes it can be difficult to locate existing holes in the firewall, and if you do find one it will appear to be so tight with wires already that it does not seem possible to get another wire through. If this is the...
    view full answer...
  • Ground Clearance of Draw-Tite Trailer Hitch 75237 on 2012 Toyota Sienna
    I sure can; when we installed the Draw-Tite Max-Frame Trailer Hitch Receiver # 75237 on a 2012 Toyota Sienna, we found the distance from the top of the receiver to the ground was approximately 11 inches. Taking into account the lip and the receiver opening being 2 inches, it will be about 8-3/4 inches from the ground to the bottom of the hitch. In regards to weight, the hitch has a total weight of 39.35 lbs. If you want this hitch to do some towing on your 2012 Sienna and needed a wiring...
    view full answer...
  • Correct T-One Vehicle Wiring Harness for a 2016 Toyota Sienna L, LE, XLE, or Limited
    If you have a 2016 Toyota Sienna LE then the correct T-One Vehicle Wiring Harness is part # 118648. If you have a 2016 Toyota Sienna SE the the correct T-One Vehicle Wiring Harness is part # 118498. These are both plug-in play options that provide you with a standard four way flat which is the most common. The T-One Vehicle Wiring Harness is part # 118648 also fits any other model expect for SE so if you have an L, LE, XLE, or Limited then this is the correct harness for you.
    view full answer...
  • Best Trailer Wiring Harness for a 2018 Toyota Sienna
    The best trailer wiring harness we have for your 2018 Toyota Sienna is going to be the T-One Vehicle Wiring Harness part # 118498 if you have the SE model with features such as daytime running lights, 4.2" color multi-information display, and a premium audio system. If you have the LE or XLE then you will want to use the T-One Vehicle Wiring Harness part # 118648. They both install in the same way which requires you to remove the tail light housings, plugging in the t-one connectors, and...
    view full answer...
  • Does a 2017 Toyota Sienna Comes With a Factory Trailer Wiring Harness
    I do not believe a 2017 Toyota Sienna comes with a factory trailer wiring harness but I do have what you need to add one, the T-One Vehicle Wiring Harness part # 118498 for SE trims or part # 118648 for all other trims. These harnesses are both plug and play options that do not require any splicing. I recommend the T-One Vehicle Wiring Harness in particular because they have the best reputation for longevity and reliability. I have attached an install video for you on both options.
    view full answer...
  • Is a Plug-In 5-Way Flat Wiring Harness Available
    We do not offer any custom-fit wiring harnesses with a 5-Way flat plug already installed, but we do offer an adapter that you can use to convert an existing 4-Way plug to a 5-Way. Using part # 20036, you would simply plug the adapter into your 4-Way vehicle plug, and then connect the additional, blue wire to your vehicle reverse light wire, behind the tail light assembly. This adapter kit includes a quick splice to make the installation very easy. You simply insert the adapter wire and...
    view full answer...
  • What Trailer Wiring 4-Way Harnesses Fit a 2016 Toyota Sienna
    If the 2016 Toyota Sienna happen to be an SE model then yes, the trailer wiring from a 2012 like the part # 118498 would also fit it. If it's not an SE model you would need to go with the part # 118648. I attached install videos for both harnesses as well.
    view full answer...
  • Trailer Wiring Recommendation for a 2015 Toyota Sienna
    For trailer wiring for your 2015 Toyota Sienna SE you would want the Tow Ready wiring harness part # 118498 as it has been confirmed to fit your vehicle. Having the 4-way run out of the back hatch is actually the preferred method although it seems like it wouldn't be. Having the 4-way stored inside the cab of the keeps it protected from rain and moisture to prevent corrosion and keeps it protected from damage to the wiring or connector by rocks or debris that might be on the highway. For...
    view full answer...
  • Trailer Wiring Harness Recommendation for a 2014 Toyota Sienna
    Most modern vehicles have more delicate taillight circuits than older vehicles. The wire that runs to the battery is used to protect the taillight circuits of your vehicle from being overdrawn by the additional load of the trailer lights. Trailer wiring harness with a wire that runs to the battery use the vehicle battery to power the trailer taillights and then only use the taillight circuits as signal wires. I can't recommend you install a wiring harness on your vehicle that doesn't...
    view full answer...

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