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Wiring for towing can be a hassle if you have to cut and splice into factory lines. The Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector plugs directly into existing tail light wiring. There’s no wire cutting or taping—just connect it at each tail light and it’s ready to go. Most installs wrap up in about an hour, and experienced hands can have it done in just minutes.
Trailer lighting draws more power than most vehicle circuits are built to handle. This harness includes a converter that keeps the trailer load isolated, so the vehicle’s own wiring isn’t overloaded or damaged. If the lights ever stop responding correctly, it’s easy to test the input and output sides of the converter with a circuit tester to pinpoint the issue.
The 4-pole flat connector provides all the basics—running lights, turn signals, and brake lights—so trailers, cargo carriers, and light-duty haulers work as they should. A solid ground keeps the signal steady and helps prevent flickering or shorts. If corrosion builds up over time, cleaning the connector restores full function quickly.
Once installed, most of the wiring stays tucked away behind trim or panels, keeping things looking clean. The only visible part is the 4-flat plug that’s ready for your trailer connection when you need it. When not in use, it can be stowed safely inside to keep it protected from dirt and weather.
Customer Satisfaction Score:
92% were satisfied with this product
8% of customers were not satisfied
Ratings & Reviews
Wiring was straight forward and direct plug in. I couldn't have asked for an easier install.
Hitch and harness I ordered came very quick! They were exactly what I needed and the instillation was fast and easy. I would definitely order from here again.
This product was shipped quickly and very easy to install. Etrailer is the best site for your trailer needs!
Fast delivery, easy and clear installation instructions!!!
Have not recieved it yet should have been delivered with the hitchat the same time
So easy to install, I installed the wiring myself. It was so easy! Took less than an hour to install hitch and wiring. It really surprised me how easy it was and it works!
SOooo easy to install, cleanSo quick, harder to read the instructions than do the job. Took about 35 minutes. This is the only way to go. I've installed brand X, which is cheaper, but always end up trying to figure out which wires to spice into and always end up doing it wrong the first time. Brand X is always a 3 hour or more job. This system is so slick, nothing to mess up and worked right first time. This "T" connector system is terrific.
This wiring harness makes hooking up wiring a breeze. I had it done in no time. I would highly stress being careful removing the tail lights. There are a couple of clips that are super thin and easy to break.
Good instructions and it worked just fine! Like that entire harness is inside the vehicle and won't get wet when not in use. Only issue is that to connect to trailer, I have to close the cargo door on the 4-wire cable. I don't want to sharply bend the cable. Must be a better way.
Great video online on how to install the kit. Worked perfectly.
The installation video makes installing this on your vehicle a breeze- takes 30 minutes tops, very helpful operator when ordering, all in all, etrailer makes picking out the parts you need very easy, and their service is great- I'm very pleased!
If you can follow instructions, and have a little bit of patience and understanding, then you will have no problems putting this harness in. Took me just around 1 hour, and that includes cleaning everything that I removed. Instruction were good and accurate. Will buy all my trailer wire harness's from etrailer.com from here out!
Very easy to install, hardest part was drilling in the ground to the vehicle. Have yet to tow anything, but the lights still work so that is always a good sign.
That was by far the easiest install I've ever done. Thanks etrailer for the great install instructions and expediting my order so quickly. I hated to pay overnight shipping but couldn't find this harness anywhere in town and was on a time crunch. All lights functioned after installing. Now off to buy my trailer! If I had any negative feedback, my kit didn't come with the double sided tape for converter. I improvised and secured it with a screw. Probably a better way to install converter anyway. Can't go wrong ordering from etrailer!
I was hesitant about buying this harness as I thought it was a little pricey, and figured I could splice the wires myself. Not to mention I wasn't sure how well it would "ACTUALLY" fit with the factory wiring. It could not have been a more perfect fit. Wires were plenty long enough, all connectors fit perfectly, wire seems to be a good gauge for the application. Installation took me about 20 minutes from start to finish. It was a breeze. I would buy this product again and recommend it to anyone. Thank you etrailer.... well done!
With the help from your [online] video it was easy to install it took only 30 minutes. The only difference between the video and the item I received was that I had to secure the transformer box there was no double-sided tape on it but it was easy to do thank you
Durwood
12/8/2020
Awesome
Hi Carla M., The Curt Trailor Hitch Receiver that you recommended for my 2005 Hyundai Tucson fit like a glove. The directions were great and it took less than an hour to install especially since my good friend has a lift in his garage. Basically all you see is the 2" receiver end. It's awesome. The Wiring Harness was a little more challenging to install and fortunately my good friend had all the right tools,and as a former autoshop teacher, the knowledge to go along with them. Don't know if I could have hooked the harness up by myself.
Works as advertised, shipping was fast and instructions were super simple. Great customer service too!
Phil S.
3/28/2018
Fantastic, no problems!
All the way from Purchase to shipping and installation went great. I've wired a couple trailers in my day but this was the first time I traced the problem to the vehicle's connections. Once I found the part on ETrailer.com I found their installation video for my vehicle. I compared that to the existing wiring and found the manufacturer had used a similar wiring adapter when we originally purchased the car. That unit had failed. No power was coming out the adapter plug causing all the trailer lights to fail. Again using Etrailer.com's video I was able to easily unhook the bad unit and install Etrailer.com's wiring to fix the problem.
Even how to remove the vehicle panel's and rear lights came in very helpful.
If you've never removed a rear tail light on some vehicles it can be a very trying thing not trying to break connectors or other parts of the vehicle. All in all once the wiring and module was connected and hooked to the trailer I was so relieved to see the tail lights do their job again. No more towing and waiting for a ticket :)
Was easy to install & works perfect. Price was for harness was reasonable & no cutting wires everything plugs in.5 stars. Also the trailer hitch,was easy to install bolts line up perfectly took my husband about 1 & half hours to harness & hitch & he took his time.
I purchased a hitch receiver kit for a Hyundai Tucson about a year ago. Since I am not super car savvy, I had my local shop install the hitch for a very reasonable price. Everything turned out great and I pull my boat behind the truck fairly regularly. The product works just as it is supposed to. It was shipped out in a timely fashion, also. In addition to the hitch kit, I also purchased a lighting harness to run from the truck to the trailer. I installed that myself in about 20-30 minutes. The instructions were easy to follow and I have had zero problems with the lights. Great products and great service. I would highly recommend!
This,by far,was the easiest time I've ever had wiring a vehicle for a trailer.The harness for a 2005 Hyundai Tucson fit perfectly-no worries
about anything not fitting,or not enough wire to reach both sides.I was
finished in about 20 minutes and was honestly stunned.
The harness arrived faster than I thought it would,and was well pack-
aged.Thanks for the great service,and I am extremely happy with the
product.
Jeff G.
6/9/2014
Still consider it the easiest tow wiring Ive ever done.
Was very easy to connect to the tail lights and works perfectly!
This is the second time I have purchased from e-trailer and they provide a wonderful service before and after the sale. The ordering is very easy on their site due to the great search engine for finding the correct items for an individual vehicle.
As for the products- well installing the wiring harness too me about 45 minutes and most of that time was spent in removing/re-installing the trim panels and tail lit assemblies. As a computer professional I only wish some of the software could be as much "plug&play as these wiring harnesses are. Every this is provided in the package and instructions are very clear and concise.
I recommend e-trailer and the T-One wiring harness to everyone needing to do a new install.
I just installed the harness after watching your video, and the install was a breeze! Thank you so much!
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John
3/19/2019
Still going strong! No issues! Great product.