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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.
Features:
Specs:
Installation
This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located in the rear cargo area. You will have to remove the plastic threshold cover, side panels, cargo trays, and interior trim panels to access this harness.
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 in 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.
A ModuLite power module is built into this T-One connector. 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.
California residents: click here
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Ellen: Hey everyone. I'm Ellen here at etrailer.com and we're going to be taking a quick look at the Tekonsha T1 vehicle wiring harness. This allows you to have the stop turn and tail light functions transferred from your vehicle into your trailer wiring or into your trailer lighting or any other kind of accessory that might use that four-pole connection.The nice thing about this kit is that we don't have to worry about cutting or splicing into our vehicle's wiring. You're not making any modifications there. You're just going to be using the plugs that come off of your taillights to plug right in line with those to get those signals. So no worries about making any changes to the electrical system of your vehicle.
It doesn't change the function of your vehicle normally. Just gives you that four pole at the back where you need it.So let's talk about what comes in the kit and roughly how it's going to be installed on your vehicle because there's a custom fit for the 2015 through the 2019 BMW X5. That's for all the models. The thing that's really nice about the Tekonsha wiring is that is a very reliable system. I've very rarely, if ever, see these comeback for any kind of issues.
They just have a really nice well-made box. So shouldn't have any issues at all with it.I think the reason for that is probably because of this potting material in the connection here or in the ModuLite box. This is where all the circuitry is or kind of the brains of the operation is and that potting material keeps out any kind of water or debris. It also helps it to be vibration and impact resistant. So as it's going down the road, shouldn't have any issues.
If it does happen to come free, where it's been mounted up to, which can happen, it shouldn't have any issues with affecting how it works. It just might be making some sounds. So just from banging around in the back of your vehicle.So you want to make sure that you mount that in a nice spot using the included double-sided foam tape. To adhere that, clean off a nice area with some alcohol and a clean cloth. Should give you a good stick to that, once you hold it in place for a few seconds.Coming off of that box, we'll have our connections to go in line with our vehicles wiring.
So you need to get access to the back of your taillights and plug those guys in line. This is where it gets the name the T1 harness. So this will be for the passenger side, the green wire, and on the driver's side, you'll get the yellow and brown. Coming off of there as well is our little black wire. That's going to go to our bulk wire and then go on to the positive side of our battery.Put the fuse holder in between that connection to the positive terminal on the battery. Comes with a 15 amp fuse so it is fuse protected. You don't have to worry about any issues arising there. The box also protects your vehicle from any kind of transfer of any electrical issues from the trailer to the vehicle and vice versa.You'll get two butt connectors, a ring terminal, and a self-tapping screw. That's going to be most likely for our ground connection, which will be the last wire to worry about here.You usually want to just find a good chassis ground for this, or if you can, find a factory ground. You can always attach it to that as well. That's always kind of nice when you can do that. And if you don't end up needing to use that screw, you can always use that to attach the box.Get a handful of zip ties to make sure that all the wiring is cinched up out of the way. If you have to run this outside the vehicle, you want to make sure that you use a lot of these to keep that wire tucked up and out of the way, secure it to several anchor points along its path and keep it away from anything hot, like the exhaust and anything moving, like the suspension.Last thing that we're going to worry about is our four-pole. This is what we're really after. So it has an occluded cap that's molded onto the base there to keep that protected. Normally, you can just run this outside the vehicle through the hatch. There should be some weather stripping, that kind of foam material or a kind of soft material to give that watertight seal. You can run it through there. It's flat enough that it can go through that without having any issues, but it's still going to seal up nice and tight so you don't have to worry about anything getting into your vehicle like water.Some people don't like the look of that. It looks a little messy. So they would prefer to have a permanent mountain next to the hitch. Definitely a possibility or definitely something you can do. Usually it just takes a little bit more work to do that. So you'll need to find a ground to go outside the vehicle, pick up a couple of brackets, including a four-pole bracket to attach it to your hitch so that you can have that sitting there next to it and then the wiring is kind of tucked up out of the way. You don't have to go through all that though. It works just fine coming out of the hatch, but that's just an option. And if you want to pick up those brackets, you can find those right here at etrailer.com.But that's pretty much all there is to it for our look at the Tekonsha T1 vehicle wiring harness. I hope this video has been helpful in deciding if this is the right fit for you. Again, I'm Ellen here at etrailer.com. Thanks for watching.
Easy to install, plug and play connectors at tail lights, no cutting/splicing of ANY factory wiring is a huge plus. Would be better if it was designed to install on the right (passenger) side rear, as there is a grommet to allow the trailer connector to pass through to the outside (passenger side behind the bumper). I wound up extending the left side tail light connector to allow right side module installation.
I installed this on a 2017 BMWx5d. The video provided be etrailer was excellent for preparation. The wiring kit installed easily with no wire splicin and has worked flawlessly since installing a year ago

Jt
10/7/2022
This harness has been great for my 2017 BMW x5 Diesel. I trailer my boat twice a month to the boat ramp and the rest of the time my wife drives the SUV. The harness conveniently hides in the left storage compartment when not in use.
The harness worked great, I had it installed in about 20 min. Just an FYI the harness fits the 2014 BMW X5 35D as well as the other years listed on the Etrailer website.
Installed and mounted easily in 2017 BMW X5 35D. Using it for lights on a cargo carrier for occasional use.
I can't believe how easy this was to connect. With the benefit of BMW placing their batteries in the rear, direct wiring to the battery for power a breeze.
Neat and easy installation. Working pe rfectly!
Fits my 2016 X5 nicely. Not having to splice into the factory wiring is a huge plus.
The installation doesn'f get much easier, quick and clean professional look.
LOOKS LIKE PLUG AND PLAY AND GOOD QUALI TY!
The directions for this install were very thorough and easy to follow. It made installation very easy.
Great product. Just plug in and connect to battery. Didn’t have to even read instructions, but did so just in case. Very easy and total worth it. Thanks!
Zero problems with install and works like a champ
The service is excellent. But it need to do a better packaging.
Easy to install, no issues.
Very easy install.
Works great, and not bad to install.
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Ryan
8/11/2022
A year later and still satisfied. No issues to report.