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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 # 118413
Our Price: $48.48
You Save: 40%
Custom Fit Vehicle Wiring

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Tekonsha Converter Custom Fit Vehicle Wiring - 118413
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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 - no cutting, splicing or tapping required. Includes tail light converter. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number 118413 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 - 118413

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • 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 - no cutting, splicing or tapping required. Includes tail light converter.


  • 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 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: 4.2 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 interior trim panels in your rear cargo area.

Once installation is complete, the 4-way flat connector will be stowed within your trunk or 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.

Tail Light Converter

A tail light converter 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. The tail light 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.

118413 Tow Ready T-1 T-Connector - 4 Wire

Installation Details 118413 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 - 118413

Average Customer Rating:  4.9 out of 5 stars   (285 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 - no cutting, splicing or tapping required. Includes tail light converter.


I have enjoyed my hitch from etrailer & installed it myself without any issues. The plug & play wiring harness was also simple & easy to install. Thank you etrailer for 2 great products!

2006 Toyota Highlander

I'm not very experienced with auto repairs/upgrades, but this was relatively easy, even for this 66 year old grandpa!! The eTrailer video covers it very well, and the only issue I had was that the adhesive-backed part didn't stick. (Yes, I took off the backing first). They even included zip ties to keep it neat.

One thing I noticed after the fact, and redid, was that in the black tray on the driver's side there is a notch on the outside wall location. In the middle of that notch there is about a 5/8 inch slot that I believe Toyota provided expressly to route out the 4 prong adapter wire. No doubt to make it easy on their dealers. That's the place to route it out from behind the panel. (See pic).

Also, I bought a Hopkins model 48625 tester that you hook up to your project to see if it is working properly. It shows you if the tail lights work, and the left and right turn signals. (You start the car, turn on the lights and work them from the drivers seat). If I have any trailer problems in the future, it allows one to test the car separately, and if that is working, then it must be with the trailer. I'm glad I bought it. Overall, a great kit. I recommend it. ETrailer shipped immediately and it came without any damage.

Bruce H.


Hi. Thanks for the follow up. The hitch and wiring work flawlessly! I bought it to haul a small sailboat and it is very rugged. Works great! I highly recommend it.

2005 Toyota Highlander

I was looking to purchase a trailer hitch and wiring assembly for my 2005 Toyota Highlander. What I found on the internet was a company called "". This company had videos showing how to install their hitch and wiring assembly for my year and model. The installation looked easy with NO wire cutting. I ordered both parts. George J from e.trailer followed up with a series of emails letting me know that my ordered and on it's way with tracking info. The order was received on time and when unpackaged everything was of high quality. My son and I installed everything in a little over 30 minutes. The videos were spot on and made installation a snap! It was a pleasure to work with this company. Jim M. Fredericksburg, VA

James M.


Great, no problem.


Was very easy to install. Worked great as soon as intalled. Very satisfied with al etrailer products. Been a customer for many years and at least 4 different vehicles.


Trevor was very helpful and professional. I appreciate the patience he showed to a new trailer owner.

2005 Toyota Highlander

Excellent product. Included everything needed for installation. The eTrailer video made it super easy. It took me less than half an hour.

2005 Toyota Highlander

I was very impressed with how easy it was to install. The hitch lined up perfectly and was on in 20 minutes, the wiring harness was equally easy to install. I would highly recommend to anyone.


Works well and was not difficult to ins tall.


Great service and correct info. Communication was perfect. Thankyou


This is the second trailer hitch I bought from etrailer Hitches were easy to install arrived quickly very reasonably priced A+ The first hitch I bought was over five years ago still going strong! Highly recommended

2005 Toyota Highlander

Worked just as it should. Easy install.


Great company to do buisness with.
I orded all the parts and they arrived in a timely manner. The box did arrive with huge hole in it due to the good ole post office not etrailer. Thanks to the way etrailer packed it nothing was lost. Yay etralier. It was easy to install just took the old 4 bolts and tow bars down and put up the new hitch and new 6 bolts. Only took about 5 minutes. The video instuctions for the wiring made it easy also maybe took 7 miutes to do wiring. Thanks etrailer for making and easy project even a girl can do. :-



It has been a year and the product is still in excellent condition. I have used it often and no complaints. Would order from etrailer again. Thank etrailer


Installed easily and has worked like a champ ever since. No issues at all. Lighting kit also a no-brainer.


Hello, My tow light system lasted about 1 month. The little black box fried itself. To be fair, it might have gotten wet. not sure. used it 1 time.

2008 Hyundai Azera

I've installed several trailer wiring kits, and this was by far the easiest one ever. except for finding a place to locate the black box and securing the wiring harness to existing guides, it was plug & play. Nice not to have to strip wires, solder, and tape connections.

Stephen W.


The wiring harness still works perfectly. I havent had to do a thing to it, except use it to power the lights in my trailer.


I got the trailer wiring harness and loved it. Received it within 3 days of order. Installation couldn't have been simpler. It took about 20 minutes and now I have lights for my trailer. etrailer support was awesome. After ordering the part I was able to go directly to a video showing how to install it.

David N.


1 year later and I still love it. I still remember how easy and seamless the installation was. I think about that every time I plug in the trailer lights. Etrailer is my go to website now.

2003 Toyota Highlander

Harness arrived on schedule and well packaged. All connections were easily made, except for the ground. Routing the wires proved difficult. I believe the tutorial that I watched was for a 2003 Toyota Highlander and the wiring harness was not where the tutorial showed, so I had to improvise in order to hide all the wires. The only wire I had to cut was the ground, in order to put a larger end on it. When finished, you'd never know I was there. The trailer plug hides nicely in the rear compartment when not needed. I'm very pleased with the final results. Thanks!

Dick B.


Still happy with the end result.

2007 Toyota Highlander

Eassy plug and play good quality of wires..Excellent product.

2005 Toyota Highlander

Generally, the wiring harness arrived quickly and in good shape. It was pretty easy to install. My only criticism is that the pictures provided on the directions weren't very good. Also, I recommend buying a 4-way flat connector tester (which etrailer sells) for about 5 bucks to be sure every thing works well before you attach a trailer to your rig.

Etrailer Expert

Heather A.


David, thank you for your review. I would recommend curts 4 way flat tester part # I26 to test your connection.


The product itself seems to work great, so I will give it 5 stars. My only concern on installation of the product was due to the lack of a self-tapping screw to provide a sure grounding. I ended up using a bolt that I questioned.
However, I then had to install a 7-pin adapter which did come with a self-tapping screw for grounding, so I'm not sure if the bolt I used was sufficient, but everything works fine now.



I never had any issues with the product. It has worked perfectly.

Toyota Highlander

Bought this for my sister'a Toyota Highlander. It worked great and was easy to install. However, after a little while, the right tailllight started not working. It turns out the plug was not making a very good connection on one side. You have to unplug and jiggle it a lot then t will come back on. Other than that, it's been great. Got the job done.

Etrailer Expert

Laura E.


Im sorry for any inconvenience, Joe. This item has a 1-year warranty. I have forwarded your review to our customer service team, who should be in contact with you as soon as possible.

2006 Toyota Highlander

Was shipped fast and a breeze to install. Fit up was perfect. Shipped with instructions and hardware pack. The 118413 wiring pack was also fantastic and a dream to install. This will work well for hauling a boat and utility trailer now. Thanks etrailer!


It's worked great. I have been towing with it for about a year with no problems.


My old trailer wiring harness was an after-market product and wasn't working properly so I tried to replace it locally. I visited a retail custom truck store in the area and described the problem and they said I should order a new one and it would be easy to replace. I ordered it, had to come back a week later to pick it up, and then took it home and found out it was the completely wrong part for my vehicle. They accepted my return but they were of no more help. I must have done a Google search and found and found exactly the right wiring harness for a couple of bucks less than I'd paid for the wrong one. It arrived in a few days later, I installed it easily using the instructions given, and it worked perfectly! No wonder brick-and-mortar stores are going out of business. etrailer provided me with exactly the right part at a fair price. Good job, guys! I'll keep you bookmarked.

2003 Toyota Highlander

Everything arrived on time. It was very easy to install just as the video described it. I will be coming back to e trailer for all my wiring needs!


David P.


Yes no problems at all, the wiring still works perfectly!

Show More Reviews

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

  • Trailer Wiring Harness Recommendation for 2006 Toyota Highlander Bypass Incomplete Factory Wiring
    Trying to complete factory wiring on a vehicle can be a headache as it can be very difficult to find out where the missing link is on the wiring of the vehicle. It's possible you could find a wiring diagram for your vehicle and trace everything that way to verify that everything is good but I have an easier overall solution that's priced pretty well too. The trailer wiring harness part # 118413 would make your life much easier. All you have to do is plug the connectors of this harness...
    view full answer...
  • Troubleshooting Trailer Wiring that Doesn't Work Only Between One Vehicle and One Trailer
    It sounds like there's something off with the connection that is made between your tow vehicle and your trailer. I would inspect the pins of both the vehicle and problem trailer wiring and see if there's something unique between those two that allows the problem only between them. Or sometimes it's a weak ground on the trailer wiring that only causes problems for a vehicle that also has a weaker ground and improving the trailer's ground can help.
    view full answer...
  • Does Trailer Wiring Harness for 2005 Toyota Highlander Require Hardwiring
    For your 2005 Toyota Highlander the correct trailer wiring kit you need is the part # 118413 which is confirmed as a fit. This plugs in line with the vehicle's taillight connectors and because of that does not require any hardwiring or splicing.
    view full answer...
  • Why Are My New Boat Trailer Lights Flickering When Vehicle Is Running
    Your issue of the lights flickering and going off when the vehicle is moving and working fine when the vehicle is stopped sounds like a classic overloaded ground issue. Ground issues usually occur when there is draw on the system from running lights or other functions like turn signals or brake lights. You want to make sure your lights are attached to the trailer's main ground and that ground is attached to a clean bare metal surface. If the trailer lights are ground through the trailer...
    view full answer...
  • Can 4-Way Trailer Wiring Harness # 118413 be Routed/Mounted Outside of a 2003 Toyota Highlander
    You will have to look for a grommet or other exit point at the very bottom of the cargo area of your 2003 Toyota Highlander. Remove the panels above and around the spare tire like you would when installing the wiring harness as shown in the video I have linked for reference. Remove the spare and look for a grommet you can run the harness through. Chance are the grommet will not be large enough to fit the 4-Way plug through. You would have to cut the 4-Way end off a few inches back from...
    view full answer...
  • Trailer Wiring Harness Recommendation for 2005 Toyota Highlander without Tow Package
    If your 2005 Toyota Highlander doesn't have the tow package you can use part # 118413 for trailer wiring. This kit installs by plugging in line with the taillight connectors of the vehicle to power the trailer lighting connector. Check out the install video I attached that shows this harness installed on 2005 Highlander just like yours.
    view full answer...
  • Installation Instructions for a Tow Ready Wiring Kit on a 2007 Hyundai Azera
    In order to install this Tow Ready Custom Fit Vehicle Wiring # 118413 you will need to run a ground wire to a clean portion of the body of your 2007 Hyundai, but you will not need to run a power wire. I attached installation instructions for you to check out also.
    view full answer...
  • Correct Trailer Wiring Harness and Installation for a 2005 Toyota Highlander Without Tow Package
    The connection points for the Tow Ready Custom Fit Vehicle Wiring for the 2005 Highlander by Toyota, item # 118413, are located behind the vehicle tail lights. You will need to remove the drivers side and passengers side access panel to locate rear of the tail lights. The threshold will also be removed and then the connectors will be connected inline with the vehicle tail light wiring connectors. I have provided a link to instructions for you to review.
    view full answer...
  • Recommended Trailer Wiring Harness for 2004 Toyota Highlander with Damaged Factory Tow Package Plug
    For your particular situation I do recommend going with the Tekonsha T-One Vehicle Wiring Harness # 118413 even though your Toyota Highlander is equipped with the factory towing package. This harness will plug into built-in ports behind the tail lights and completely bypass the factory plug that the previous owner messed up. This will ultimately be a much easier installation than trying to re-wire and fix the damaged sections in question. I have attached an installation video on the 2004...
    view full answer...
  • Troubleshooting Trailer Running Lights That Flicker and then Turn Off
    Sounds like it could be a ground problem, the additional load of the running lights being on your vehicle is too much for the weak grounds and the circuit is shutting off. Or the problem is your trailer taillight circuit is drawing more amperage than the wiring harness is capable of handling. You might try disconnecting a few of the running light circuit clearance lights to see if this allows the lights to illuminate. If so, you will need to convert your trailer to LEDs. I attached a link...
    view full answer...
  • Comparision of Wiring Harness 33425 and 118413 for a 2002 Toyota Highlander
    You basically answered your own question. The more expensive 33425 wiring harness has circuit protection and is powered so that you can tow trailers with more lighting. You will need to run a wire to the battery from the converter box to use this connector. The 118413 will work fine if you are towing trailers with just one set of lights at the back and no extra lighting. However, it will not protect the vehicle and converter from shorts at the trailer. Both kits come with instructions...
    view full answer...
  • Factory Tow Package Connection Point to Install Trailer Wiring on a 2005 Toyota Highlander
    If your 2005 Toyota Highlander came with the factory tow package then the factory connection point to add a 4-Way will be located behind the driver side interior trim panel in the rear cargo area of the vehicle. You would then use wiring harness # 118248. I have linked a video showing installation and a link to the instructions for you. If that connector is not present on your Highlander then you will need to use harness # 118413. This wiring harness just plugs in line with the vehicle...
    view full answer...
  • Will Wiring Harness Part # 118248 Fit a 2007 Toyota Highlander without a Tow Package
    The 118248 is only for 2007 Highlanders with a tow package. If you do not have a tow package, you would use part # 118413.
    view full answer...
  • Does My 2007 Highlander Hybrid have the Tow Package Wiring Connector
    To determine if you could use the Tow Ready wiring harness part # 118248 on your 2007 Toyota Highlander the most efficient way would be to determine if you have the trailer wiring connector on your vehicle, and then use a circuit tester like part # 3808 to determine if the pins on it are active. If both of those things check out the # 118248 would work well for you. To see where this connector is check out the 45 second mark of the install video I attached to the right. Otherwise you...
    view full answer...
  • Custom Fit Trailer Wiring Recommendation for 2007 Toyota Highlander
    I have a better trailer wiring solution that will cost less and will install much easier on your 2007 Toyota Highlander. For that you'd want the part # 118413 which is a custom fit harness for your vehicle. I attached an install video for this for you to check out as well that will walk you through it. An install instructions link is also attached below as well. The Hopkins kit is a universal style kit and would require you to go in and test the wiring of your vehicle and then splice into...
    view full answer...
  • Reliable Trailer Wiring Recommendation for 2004 Toyota Highlander
    Based on the troubleshooting you've done so far you have a shorted out converter box of your trailer wiring harness. The only solution in this scenario is a new harness. For that the Tekonsha brand like part # 118413 is our most reliable option so it would be what we recommend for your 2004 Toyota Highlander. I checked our order notes and was not able to find you in our system also. Based on that I don't believe you bought the kit from us.
    view full answer...
  • Trailer Wiring Harness Recommendation for a 2003 Toyota Highlander without Factory Tow Package
    For a 2003 Toyota Highlander without the factory tow package you can use T-connector # 118413. It does not require a connection to the vehicle battery. I have included a link to the instructions and a link to a video showing a typical installation for you.
    view full answer...
  • Trailer Wiring Harness for a 2005 Toyota Highlander
    First, on your existing wiring harness, since there is power going in but not coming out on the right side circuit then that does indicate a problem inside the converter and it will need to be replaced. If the harness you currently have looks like # 118248 then that indicates that the vehicle came with the factory tow package. To confirm you can always contact at Toyota dealer and have them run the VIN number to determine how the vehicle is equipped. If your Highlander does not have...
    view full answer...
  • Trailer Wiring Recommendation for 2005 Toyota Highlander without Tow Package
    Most likely what you need is the part # 118413. This is the recommended trailer wiring kit for your 2005 Toyota Highlander if it did not have the tow package. Since your vehicle doesn't have wiring already you wouldn't want the other kit part # 118248 as it is designed as a factory replacement. I attached an install video for you to check out as well.
    view full answer...
  • Trailer Wiring Harness for a 2005 Toyota Highlander with Factory Installed Tow Package
    Since your 2005 Toyota Highlander came with a factory tow package, you would need Tow Package Wiring Harness with 4 Pole Trailer Connector, # 118248. I have included a link to the installation instructions along with a link to a video showing a typical installation for you to view.
    view full answer...
  • Recommended Wiring Harness for 2005 Toyota Highlander
    The Tekonsha T-One Vehicle Wiring Harness # 118248 referenced in your question will work great on your 2005 Toyota Highlander if it has the factory tow package installed. The T-One Connector will simply plug into the OEM ports located behind the driver side trim panel on the vehicle. You will not need to run a wire to the car battery. If your Highlander does not have the factory tow package, you will instead want to use the Tekonsha T-One Vehicle Wiring Harness # 118413. This will plug...
    view full answer...
  • Adapter to Go from 4-Way Flat on 2002 Toyota Highlander to 5-Way Flat on Trailer
    What you will need to connect the 5-Way flat trailer side connector to the 4-Way flat connector on your 2002 Toyota Highlander is adapter # 20036. This adapter does have that extra blue wire that taps into the reverse light circuit on the vehicle. This is used to a activate an electric lockout solenoid on surge trailer couplers so that the trailer brakes do not apply when you are backing up.
    view full answer...
  • Replacing Tekonsha 4-Way Flat Vehicle Wiring Harness That Failed
    I have not heard of anyone having that issue with the Tekonsha T-One Vehicle Wiring Harness # 118413. Any alteration to the wiring harness is not recommended and would void the manufacturers warranty. I recommend using the Hopkins Plug-In Simple Vehicle Wiring Harness # 33425 as this will allow you to use a fuse on the main power wire that transfers power to the module. This harness will not draw on the vehicle wiring like the Tekonsha kit.
    view full answer...
  • Trailer Wiring Recommendation for 2006 Toyota Highlander to Replace Shorted Harness
    Trailer wiring converter boxes are designed to absorb the shorts in trailer wiring and basically sacrifice themselves to prevent your vehicle wiring from getting damaged. That's what happened in your case. That extra wire you mentioned is used for drawing power for the trailer taillights instead of drawing them from the vehicle lights. This is another way it protects the wiring. The part # 118413 does not use a wire like that. Since I prefer that type of install since it's safer I would...
    view full answer...

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Info for this part was:

Employee Mike L
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