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

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

Item # 118498
Our Price: $70.93
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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. 1-800-496-5010 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 - 118498

  • 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

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   (180 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.

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.


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.

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! :)

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.
Kelly H - 08/12/2015


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…

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.
-- Etrailer Expert Jenny N - 11/16/2022


Works great. I tapped into the 12V power plug in the back of the van to avoid running wiring all the way up to the battery.

2016 Toyota Sienna

The item had the wrong connectors that go in-between the vehicle wiring harness and the taillight assembly. I had to splice them in with the old set.


Worked great, towed a trailer cross cou ntry


Simple and easy to use one caveat, it does necessitate the running of a wire to the battery. If they could find a way to power the harness from the taillights, it would be a no-brainer. Otherwise, it has been a wonderful purchase. I might add that the video was wonderful, keep it up trailer!!!

2014 Toyota Sienna

Generally easy to install and straightforward. It does REQUIRE some other piece of wire or cord to fish the wire that runs to the battery up into the engine bay. They also recommend a pull wire to drop that same wire down from the left taillight to the bumper and under the van though I didn't find that necessary. 3 stars rather than 5 because that same long black wire (runs from the back of the van, under the van and up through the engine bay to the battery) is too short. It just BARELY reaches the correct spot so you only have an inch or so of play in how you run it under the van and it's a pain to get into the engine bay. There is no reason why this wire couldn't be 6 inches longer (other than cheaping out on the production cost) to make the install A LOT easier. Even in the install videos it just barely reaches and mine ended up being an inch or two shorter than what's seen in the video which probably has to do with the routing path.


Watched the video prior to attempting installation. Took me a little less then two hours to complete. I did run the power wire under the trim pieces inside the vehicle and up under the dash behind the glove box instead of running it under the car as shown in the video. Everything plugged in and worked perfectly.


Everything that was needed was included in this kit, was of good quality, and worked. The instructions were not particularly clear, and the time and effort needed to install it was not explained well, possibly even a bit misleading. We ended up having a professional mechanic finish the installation, and it even took him longer than the estimate (admittedly, having to deal with our having started it, which never helps)

I recommend watching our video installation on a 2014 Toyota Sienna and our FAQ on routing the power wire to the battery.
-- Etrailer Expert Jenny N - 04/25/2022


Dude works hella nice for my 2014 Toyota Sienna Limited.

Toyota Sienna

Easy to install and works. I'm a neophyte when it comes to this kind of stuff but the directions were clear. The only downfall was installing on a Toyota Sienna van which has zero clearance underneath. Took me a few extra hours working the wire up to the engine compartment to the battery. It would have been so much easier if it was on a lift for better access. Have plenty of zip ties handy.

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.


Everything went together great except the power wire that goes up to the battery was too short and I wired it according to the diagram…but otherwise a high quality product.


I needed a trailer hitch for a "new to me" 2012 Toyota Sienna Limited.
The Sienna has multiple hitch options. Terry N. was super knowledgeable and a pleasure to work with. She very patiently helped me choose the best hitch and wiring options and found a localtrailer expert to install it for me, all for less than UHaul wanted for their inferior product!

As if that wasn't enough ..........she also got me very affordable expedited shipping which arrived 24hours before promised!
My first time using etrailer but it won't be my last!
Thank you Terry N. I love you!!!
I'll send photos after the installation this afternoon.

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!

2022 Subaru Crosstrek

I deserved to know I was buying an open box item

When the harnesses are shipped to us they are shipped in large pallets which can cause the clam shells that hold the harness to become opened. As long as where is no damage to the part we will reseal the clam shells prior to shipment. I will have our customer service team reach out to you.
-- Etrailer Expert Jenny N - 09/19/2022

2013 Toyota Sienna

Just installed it today and seems to work fine on my 2013 Sienna.


Great equipment!! Fast delivery


Clear directions and fit my 2011 Toyota Sienna perfectly


Worked well. Good directions

2013 Toyota Sienna

Install went exactly as described in the installation video, I did the work myself with a set of ramps to elevate half the van at a time.


Great product, easy to follow instructions and installation.


Worked just as advertised

Show More Reviews

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

  • Recommended Trailer Wiring Harness with Powered Converter for 2014 Toyota Sienna
    Since your 2014 Toyota Sienna uses a separate wiring system a circuit protected modulite is required to protect the van's wiring. That's why all the harnesses confirmed to fit your Sienna have the powered converter. Out of the selection I suggest the Tekonsha # 118498. It does plug in behind the tail lights, like you said and will give you a 4-way trailer connector on your van. I've attached an install video for you to take a look at.
    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...
  • 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....
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    Image 1 for
  • 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...
  • 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...
  • Where do the Brown and Red T Connector Wires connect on a 2011 Toyota Sienna
    For installation of the Tow Ready Custom Trailer Wiring Harness, item # 118498, on the 2011 Toyota Sienna, you will need to insert the T-Connector ends with the Green wires and coneectors with Brown and Red wires between the vehicle wiring connectors and tail lights and lock into place on the passenger side. You will then, Route the T-Connector end with the yellow wire to the driver side behind the panels and along the threshold and connect between the wiring connectors and tail lights...
    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...
  • 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...
  • 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 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...
  • 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
  • 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 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...
  • 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...
  • 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...
  • 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...
  • 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...
  • 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...
  • Which Trailer Wiring Harness Will Work With 2017 Toyota Sienna LE
    The difference between part # 118648 and part # 118498 is that part # 118498 is designed for the SE model and part # 118648 is designed to work with Siennas that are not the SE model. Since you came from the non-SE model the trailer wiring harness that will work for you is part # 118648. This trailer harness is a simple installation. You just plug it into the connection points behind the driver and passenger side tail lights and then run the hot lead wire to the positive battery post...
    view full answer...
  • Trailer Wiring Harness Recommendation for a 2005 Chevy Equinox
    There are a couple of options for trailer wiring harnesses that fit your 2005 Chevy Equinox. I have included a link to the right to them for you. The prices are also listed. Out of the options I recommend # 118391. It is the more popular option, cost less, and works well. I have linked a video showing how it installs on a 2005 Equinox for you.
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  • Are the Curt Trailer Hitch and Vehicle Wiring for a 2010 Sienna the Same as a 2011 Toyota Sienna
    Yes. The Curt Trailer Hitch, # 13105, will fit the 2011 Toyota Sienna. Often times, manufacturers will make little to no changes to the chassis, frame, or any number of components between model years. In this case, the 2011 model Toyota Sienna retained the same mounting locations for a trailer hitch as its predecessor. I have included a link to the installation instructions below. I have also included a link to a video install of this hitch on a 2004 model which, coincidentally, shares...
    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...
  • 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...

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