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Wiring a trailer doesn’t have to mean cutting into your vehicle’s factory wiring. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector plugs right into existing connectors for a clean, straightforward setup. It’s a hidden, plug-in design that keeps everything neat and out of sight, so you get a factory-style install without any guesswork.
This harness gives you a standard 4-flat plug that runs your trailer’s brake lights, turn signals, and taillights. It’s the connection most small trailers use, so you’re ready for boats, campers, or utility hauls as soon as it’s installed.
Some vehicles need signal conversion to work with trailer wiring. This harness includes an integrated converter that manages that automatically. You don’t need an extra module or separate conversion kit—it’s all built in and ready to go.
Once installed, the harness stays tucked away using factory grommets and trim paths. The plug-and-lead setup keeps wires protected from the elements and inside the vehicle until you’re ready to tow. It looks clean when not in use and connects easily when you need it.

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hello everybody, this is Jeff at etrailer.com. Today, we're going to take a look at this CURT T-connector vehicle wiring harness, with the four way, flat trailer connector. Now, this harness is a custom-fit part. It is designed to fit the 2019 Toyota Avalon vehicles. On a custom-fit part like this, I do recommend for you to go to our website, use our fit guide, put your year and model vehicle and it'll show if this'll work for your application. Now, this harness will provide this four way flat trailer connector at the back of your vehicle to power your trailer's signal lights.
It is compatible with five pole, six pole and seven pole adapters that we do sell separately on our website. This does connect very quickly and easily. You just locate your connection points, which are behind the tail lights, in the trunk, plug in these connectors, one on each side, ground your white wire and then run your power wire to your vehicle's battery.Now, it does include this black box here, which is your tail light converter. This is to ensure that your vehicle's wiring will match that of your trailer. It is a powered module.
That's why it'll connect directly to your vehicle's battery. That's to avoid overloading your vehicle's electrical system. This converter is constructed using SMT technology, which is surface-mount technology, gives you more consistent, reliable performance. It does maximize your trailer light yield and intensity, while producing minimal heat, and it does ensure superior operation in any rough road conditions. Also included, they have this nice, rubber dust cover for your four way.
Basically, what you can do with that is, just attach it to there. You can leave it on there if you'd like. Then, when you're not plugged into your trailer, you just put that over your terminals and that'll protect them from any damage, or from the elements.A few specs on this harness, maximum amperage on the stop and turn light circuits is three amps per circuit. On the tail lights, it's six amps per circuit. I'm just going to briefly go through where all these parts...
Everything shown here on the table is included. They do have a nice set of detailed instructions. That will describe how it installs and where your connections are made, but basically, what you want to do is, start at the rear of the vehicle. You'll probably want to start on the driver's side. You'll take this T-connector that has the red and yellow wire in it. That's for the driver's side. You'll go behind the tail lights, unplug the harness, plug this into there. Then, you'll take the other T-connector, which is for the passenger side. You can see it as this length of green wire on it. This'll run over to the passenger side. You'll do the same thing, plug this in behind the tail lights.Now, on the driver's side here, you'll notice this white wire with the eyelid on it, that comes out of this section sire. This, you do want to connect to a good, clean ground, if there's one nearby. If you need to make one, they do include a grounding screw. Then, this converter box does have a little weight to it, so you don't want it bouncing around. You do want to attach this to a nice, flat surface. They do include this piece of double-sided tape here, that you can put on there and attach it down.Then, your last wire is your black power wire. This will need to run to the front of the vehicle, to attach to the battery. They do give you this length of wire to do that and the connectors. If you take a butt connector, attach it to there and then attach it to one end of this wire, run this wire all the way up to the front. When you get to the front, you don't want to connect this directly to the battery. You want to run it through the inline fuse holder. You take your other butt connector, attach it to one end of this fuse holder. Then, take your eyelid connector and attach it to the other end of the fuse holder. That is what'll connect to the battery. Once it's connected, just take the included 10 amp fuse, install it in your fuse holder, put your cap on the fuse holder and your system's all ready to go.If you noticed, they do give you some extra cable ties to take up any slack in the wiring, but that should do it for the review on this CURT T-connector vehicle wiring harness, with the four way flat trailer connector.
Ratings & Reviews
the four prong plug is missing
This kit was so well designed it went in without any issues.
Info for this part was:
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Katrina B.
12/8/2022
We are sad to hear that your order arrived missing the plug. I have sent this information over to our customer service team for them to contact you.