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Struggling with complex wiring harness installations? The T-One Vehicle Wiring Harness with its 4-Pole Flat Trailer Connector offers a straightforward plug-and-play design. Just connect it to your vehicle's existing wiring—no splicing or cutting required. It fits seamlessly into the factory connector, often located behind the spare tire, making it a cinch to set up in your Toyota Sienna. Many users find it takes just about 15 minutes to get everything ready, even with distractions along the way.
Worried about overloading your vehicle’s electrical system? This T-One wiring harness includes a ModuLite power module that connects directly to your car battery. This clever feature ensures your trailer’s lights are powered efficiently without putting extra strain on your vehicle's circuits. This means you can tow confidently, knowing your system isn't being overworked.
Ever bought a product to find out it doesn't quite fit? Not with this one. The harness is custom-designed to fit Toyota Sienna models perfectly, ensuring ease of installation and optimal functionality. Customers have praised how it fits seamlessly into their vehicles, providing all necessary signals to the trailer without hassle.
Worried about weather ruining your electrical connections? The T-One harness is constructed with 16-gauge bonded wire and includes a dust cap for the 4-way flat connector, perfect for keeping connections clean and protected from the elements. Applying a small amount of grease to connections further helps to prevent corrosion, ensuring longevity and reliability, whatever the weather throws your way.
Need to connect different trailers? This wiring harness doesn’t stop at 4-way. It’s also compatible with 5-pole, 6-pole, and 7-pole adapters for ultimate versatility (adapters sold separately). So whether you’re towing a small trailer or a larger setup, this product supports a range of configurations, making it a versatile addition to your towing toolkit.
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2024 Sienna XLE installed easily, just plugs in, but side panel removal takes some thinking. Watch the video for similar products. Get a cheap panel removal tool and life is easier! Used small machine screw to bolt relay box above the small removable panel.
See photo. If ever needed this allows access to the units fuse holder without having to go through the work of removing side panels again. Routed trailer wire out bottom of this small panel and wiring then stores neatly in the side box.
The Wiring Harness Arrived on the promised Date, inside the Box with the Hitch I Ordered. Great Idea! to Ship both together. I have a less common version of the Sienna with a spare tire which the instructions don't really take into account the obstruction the tire creates in installing and positioning the module but I made it work so it doesn't get damaged by the Tire location. The Connection Point is farther away from the previous Sienna I had installed (2021 vs a 2025). The need to work around the tire resulted in the pigtail to the trailer being a little shorter than the previous 2021 install resulted in. I made a 2 FT. extension cable out of some trailer wiring I had left over from previous re-wiring projects I did for myself and friends trailers to avoid risking pulling on the trailer's harness too much in a right-hand turn or Back-up situation. All in all the install went well as it should have. Sorry but I didn't think to take any pictures of the completed Install. I like this harness because it didn't need wires run to the battery for power (No Brake circuit needed for light duty trailers).
Fits perfectly on my 2022 Toyota Sienna XLE and was very easy to install.
Simple installation. Good quality product. I've been using it for over a year now with no issues.
Craig
12/9/2024
Actually been using this wiring harness for 2 years now. It has help up well. Still performing as it did when new.
I was able to just plug and play.
Plug and play made everything very simple another very good product
I have not tested it yet, but installation went fairly smoothly thanks to Toyota having a connector in the rear of the van. Accessing the compartment was not quite as easy as depicted on the video, and one of the plastic plugs fell out of sight, so there is now a slightly loose panel. Otherwise, helpful instructions from etrailer.
Easy to install. Perfect for our 2024 Toyota Sienna. Very pleased. There is a ground on the driver side rear panel near the spare tire. Some models don't have a spare. Good luck.
Easy to install, would recommend partially removing the bumper (primarily on wiring harness side) IF you do not have the spare tire option.
Excellent fit, Easy installation. Definitely buy this version instead of the one that has to be spliced in.
Easy installation with clear instructions. Very well packaged. Arrived very fast and the customer service was great! I knew where my product was at all times and when it arrived at my house.
Anthony B.
5/14/2024
No issues have presented themselves since it has been installed. Still working as it is supposed to.
This worked great on our '22 Sienna. Things plugged right in. I got a little creative with the mounting and wire routing. I mounted to the back side of the plastic access panel, then cut a notch in the access panel to run the wire through, into the rear cargo area. It's worked out well for me. I have the flat four with wire coiled up inside the rear cargo area of the vehicle, which wouldn't be ideal for somebody using the trailer all the time, but for me, using the trailer 5-10 times/year, it's just fine and keeps things out of the weather.
I just installed it, and the materials were of good quality. I have not used it yet, though.
Starting at 5:15 out of 12:08 hitch installation you tube video by MasterJacks, followed his guide. Broke plastic installation pins, bought Ford plastic pins at Autozone, Toyota pins not close to OE. Used adhesive backed hook and loop fasteners to mount electronics box. Everything works.
Wiring harness connected right up to the 2022 Toyota Sienna. It comes with some Tape and mounting instructions that didn't quite line up with a Sienna that had a spare tire. I don't like 2 sided tape because I don't believe it will last in a hot car. I got a couple of self tapping screws and mounted the plastic box to the aluminum spare tire mount. Also used a self tapping screw to attach the ground to the aluminum spare tire mount.
Hooks right up to an open connector behind the spare. There’s a rubber plug that goes through the bottom of the car, I used a knife to cut halfway through it and just slid the harness into the middle of the plug if that makes sense. Ran the wires to the hitch without a problem. Dropped the plug back in and it basically molded around the harness wires. Hooked up a trailer and it worked great
The 2021 Sienna has the connector underneath the spare tire, two mounted screws perfect for the grounding wire, and a rubber cover for easy access to underneath the vehicle to route your 4-way.
The trailer hitch receiver was easy to install, but the instructions were also wrong (removing the cover underneath the car was on the driver side, and not the passenger side). 5 stars as long as they get the instructions fixed so people don’t unnecessarily tear apart their car!
Excellent. Five stars.
Very easy to install, took me about half an hour. Only minor complaint is that there were a few small spots on the hitch that were not powder coated, so I’ll touch those up with enamel. I was also able to trim the underside panel a little more conservatively so as to leave the aft bolt attachement in place. Maybe not a big deal but given that it’s plastic and supposed to protect wiring from salt and road grime, I figured leaving as much intact as possible would be a good thing. etrailer shopping and follow up were great
Incredibly easy install. The Sienna has a wiring harness behind the spare tire so it was plug and play. I was able to use one of the rubber grommets to route the wires to the hitch.
Installed it myself and towed my camper from NC to Cali with it! Worked great and held up the whole time!
It was simple to install!!! It was just as it was described.
Pritchard
2/19/2024
It was easy to install and works great! It was just as it was described.
Thos wiring kit works great and fits perfectly under the spare tire where the connector is located. The tekonsha kits Instructions say to pull panels and look under carpet by rear seat in hatch area. Wrong. That's too much work and you'll get no where but once you figure it out it's perfect and easy to install.
Installation was a breeze. No wire splicing. Plugged into my 2021 and it's been working great!
Tomas
4/27/2023
still going strong!
Works well. Instructions OK, though could be clearer.
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Dorian
2/25/2025
Product is excellent! I have used it a lot in the last 2 years and have never had any issue with it.