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Gone are the days of complicated wiring and tangled cords. With the T-One Connector, installing a 4-way trailer connector on your vehicle is as easy as plug-and-play. Just connect it to your vehicle’s OEM tow package port, located conveniently behind the rear bumper. No splicing or cutting means you spend less time setting up and more time on the road.
Whether you're towing small trailers or larger campers, this wiring harness has you covered. It's built to work flawlessly with 5-pole, 6-pole, and 7-pole adapters (available separately), allowing you the flexibility to tow various trailer types without missing a beat.
Towing frequently? No worries. This harness is constructed with durable 16-gauge bonded wire, ensuring long-term reliability. Plus, the included dust cap keeps the 4-way flat connector clean and working perfectly, making it ideal for those on-the-go adventures.
With a maximum amperage of 7.5 amps per circuit, this harness provides a steady and reliable connection to power your trailer's signal lights. It's perfect for maintaining clear communication signals between your vehicle and trailer, especially during long hauls.
Why pay a dealership to install your wiring when you can achieve a professional look on your own? The mounting bracket (sold separately) can secure your connector beneath the vehicle near the trailer hitch for a clean, integrated appearance. It's DIY-friendly, saving you time and excess expense.
If you despise the idea of incompatible parts, this T-One harness is the perfect remedy. It’s designed as an exact replacement for damaged factory wiring harnesses, ensuring that you get the precise fit and function your vehicle needs to stay trail-ready.
This custom-fit T-One connector plugs into your vehicle's factory tow package wiring harness, which is located behind the rear bumper, on the driver's side.
Once installation is complete, the 4-way flat 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.
California residents: click here
Little hard to install under the back panel but the instructions were great. I knew exactly what to do.
I purchased this thinking it was all I needed. It turns out I needed the other part as well and I couldn’t find a tutorial or anything to let me know. So when I bought the other piece I needed it came with this one. There is no option to just buy the other part. Now I have two and only need one. It is too difficult to return with me having to pay for shipping it back too. I will break even and it’s not worth my time to bother with it. It’s too bad that the web site doesn’t warn you about it and give you both options. Lesson learned, I’m currently waiting on the other part to get here maybe in a month or so(back ordered). Then I can install it and finally use my vehicle the way I want too.
Until then frustratedly yours
Arty Palmer
4th time dealing with etrailer. Loads of options, good pricing, quick delivery.
Ordered this simple trailer connector December 12. Very small part and chose to have it sent economy (=USPS). The post office was overwhelmed and providing substandard service. Thanks again 2020. I contacted trailer on Dec 21 and spoke to Danielle. I explained how I needed the part for a post Christmas need and really had expected it to have arrived already. Danielle was very professional and listened carefully. Although it was still to early to initiate a call she said she’s would follow up the 23rd. AND she did, I received an email from Danielle with a status from the postal service and some kind words assuring me that it was on the way. It did arrive on Christmas Eve as described. The review is: disappointed with the post office and highly recommend the outstanding customer service from etrailer!! And the wiring adapter is good too.
Part works as advertised. Box got smashed by the trailer hitch during shipping, part was undamaged.
Amazing service as usual!!
Excellent product and service
Perfect fit
Perfect fit to what I was looking to do.
plug and play. although if your vehicle doesn't have the factory tow package as an option you will need the "convertor" box.
Exactly what I needed.
I'm disappointed with etrailer. I have used them in the past with excellent results....but this time service was not so good. Ordered a hitch and wiring for my wife's 2024 Toyota Highlander. The Curt hitch was installed no problems. Wiring was a nightmare. First attempt received a converter and wiring that would require me to splice into the wires. Second attempt received the converter with 10 pin connector, but the 4 pin wiring/connector does not fit a 2024. This is the third attempt, and hopefully this will finish the job.
The TK74FR t-one connector plugged right into my 2022 Highlander. Easy to replace
Simple install
It is made clear that this harness is for a vehicle equipped with the factory tow package. What is not clear is that if you have the harness plug on your vehicle, that is not indicative of having a tow package. Granted there are other components that would be obvious that a tow package is present, but it seems logical that if the connection is present, it should work. In order for the trailer lights to work, you need a converter box. Some sites show it as a 4/7-way pug adapter, but the picture is wrong, keep checking other sites to see the actual device. Also, there are plenty of forums that discuss this problem. The converter powers up the harness and the connection will work. The converter, which is simple to install, is about $xx from [dealership]. The kit supplied by etrailer is way more involved than the factory converter. Just be aware that the presence of the factory plug itself is not indicative of having a tow package.
Product as advertised...exact match for our vehicle. Plenty of wire length to reach the hitch.
Joe 
6/3/2024
Durable, reliable, quality product. No issues whatsoever.
Great fit for a fraction of the cost. Easy to install and great documentation. I recommend following the forum for lots of tips on how to DIY this.
Consistently efficient and reliable ser vice
Exactly what I needed for my highlander, easy install
Great price and so easy to install if you have the towing package. This item, along with a hitch, was shipped the same day as I ordered it. Easy to use website, great customer service and well edited videos. There’s nothing else to say but Thank You!
Easy to install but doesn't work. Did some additional research and maybe should have bought the TK99FR which comes with some additional adapter or something. But nowhere did it say to research this possibility before ordering. You see the TK74FR stated clearly that it would fit my vehicle. Frustrating!
Tyler M.
6/1/2021
Hi Maureen, Thanks for our feedback! This kit is for the 2020 Highlander with the factory tow package. For your Highlander, it sounds like you will need the T-One Vehicle Wiring Harness, part # TK99FR , for Highlanders without the factory tow package.
Helpful Links
Great product. I w8sh there was a warning that there is a relay that you have to buy in 9rder for the wiring harness to allow power to and light up the trailer but I found that at my local Toyota dealership
Installation was a breeze. Following the video and with the aid of a friend, the hitch slipped into place without any hassles. Used the Pig Tail I purchased with the hitch which is "plug and play". Completed the task with the purchase of the Toyota Highlander Tow Converter from a local Toyota Dealer. The Quality of the hitch speaks for itself! IMHO, the hitch looks superior to the "through the bumper" OEM assembly.
The wiring harness came with just the wires, no mounting bracket, no zip ties, and no instructions. I wish it had some sort of mounting bracket. We had to zip tie it to the hitch receiver to keep it from trailing on the ground, which looks pretty ugly. Otherwise, it works well.
As we setup the car for pulling a trailer, this was a super easy to install setup. Requires a little digging in the car however, once you find the jack int eh car, this harness is perfect.
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Katrina B.
5/31/2022
You are correct, if you do not have the factory tow package, then you will need to have a converter box for the installation. There have been instances where the Toyota Highlander does have plugs that will fit but are not activated. When this happens, it means that you actually would need to activate the tow package with a fuse. In order to get that confirmation, you can contact a Toyota dealership to find out. If you do not have the tow package then you would need part # TK99FR.