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Wiring up a trailer is usually a hassle, but this Curt T-Connector makes it simple. It’s a plug-in harness that connects right at the vehicle’s existing plugs, so there’s no need to cut or splice wires. Just plug it in and you’ve got a solid connection ready for towing.
This harness comes with a 4-flat trailer connector that handles running lights, turn signals, and brake lights. It’s the standard setup for most small and mid-size trailers, giving you all the basics you need for safe, legal towing.

A powered converter keeps the vehicle’s delicate wiring safe by drawing power directly from the battery instead of the tail light circuit. It helps prevent overloads and makes sure your trailer lights work reliably every time you plug in.
For vehicles that didn’t come with a factory tow package, this harness fills the gap perfectly. It’s made to integrate neatly with the existing wiring and trim, giving you a tidy setup without extra drilling or loose wires hanging around.
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Today we're going to review part number C55570. This is the CURT T connector vehicle wiring harness with the four way flat trailer connector. Now, this is a custom fit part. It is designed to fit the 2004 to 2009 Nissan Quest vehicle. On a custom made part I'd always reccommend to go to our website, use our fit guide, put in your year and model vehicle, it'll show you if this will work for your application. So this harness will provide this four way flat trailer connector at the back of your vehicle to power your trailer signal lights. It does connect very quickly and easily, there's no cutting or splicing the wires. Basically you just locate your connection points which are in the rear cargo area, plug in your T connectors on both sides, and then plug the wire ...
This black power wire plugs into a mating connector that's next to the tail light wiring harness on the driver's side . And then you have this last white wire with the eyelet on it that should give the connector a good clean ground. Once that's all connected run your bonded wire out the back with the four way on it and it'll will plug in and provide power to your trailer signal lights. This harness does include this tail light converter and this is to ensure that your vehicle's wiring match that of your trailer. This converter is constructed using AMT technology which is surface mount technology. This will give you consistent, reliable performance, even maximizes your trailer light yield and intensity, and produces minimal heat. Also gives you superior operation in any rough road conditions. Also comes with this nice dust cap for your four way.
So, all you have to do is just install this onto the plug itself. You can leave it on if you'd like . Just like that. When you're not plugged into your trailer put your cap over your terminals and it'll protect from any damage, arcing, or elements. A few specs on this harness, the maximum amperage for the stop and turn light circuits is three amps per circuit. For the tail light circuit it's seven point eight five amps total. It does come with a nice set of detailed instructions that will tell you how to install it, and then it even gives you pictures showing you where the connection points are. It does come with everything shown here.
I'm going to show you in a minute how these all will connect when you install it. So basically what you want to do is go to the rear of your vehicle, into the rear cargo area and get access behind the tail lights. What you want to do is start on the driver's side and take the key connector harness that has the yellow wire in it . That's for the driver's side . Go ahead and unplug the harness from the tail lights, this will plug in behind that. And then we had mentioned also on the driver's side you have this single black wire with the connector on it, there will be a connector that will match this on the driver's side also.
You'll plug this in so you get the power. You'll see this longer length of green wire, this is for the passenger's side. Run this over to the passenger's side same way behind the tail light, unplug it, plug this in line into it. Then your last wire is this white wire with the eyelet on it. This is for your ground, what you'll want to do is find a good clean ground. If you need to make one they do include a grounding screw that you can drill a hole, put your screw in and ground it to get your good clean ground. Then your converter you want to attach to a nice flat surface so it doesn't bounce around. They do give you double sided tape to put on it to attach it down, and also some longer cable ties to adhere it down also if you need to, and then some shorter cable ties if you need to take up any slack in the wiring. There is one last thing, you need to install this ten amp fuse into your fuse box at the front of the vehicle. There'll be a location if you look in your owner's manual. Also in your instructions it'll tell you where to put this fuse in the correct location. But that should do it for the review on part number C55570. This is the CURT T connector vehicle wiring harness with the four way flat trailer connector. .
Ratings & Reviews

Dennis M.
8/27/2021
Just fine.
Info for this part was:
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Nick S.
12/22/2025
Typically the most common issue when lights are sometimes working and sometimes not is either a bad ground connection, or loose connection with the tail lights. I would recommend re-grounding the harness somewhere new and double checking all your connections, or the side that has the issue.