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Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Item # C89FR
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Custom Fit Vehicle Wiring C89FR - 4 Flat - Curt
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Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring. Powered converter reduces strain on wiring system and is made using SMT to ensure superior performance. Call 800-298-1624 to order Curt custom fit vehicle wiring part number C89FR or order online at etrailer.com. Free expert support on all Curt products. Guaranteed Lowest Price and Fastest Shipping for Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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Curt Custom Fit Vehicle Wiring - C89FR

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • Converter
  • Curt

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring. Powered converter reduces strain on wiring system and is made using SMT to ensure superior performance.


  • Provides a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Connects quickly and easily
    • Locate connection points behind tail lights
    • Plug in T-connector
    • Run hot lead to car battery
  • Includes a tail light converter to ensure that your vehicle's wiring matches that of your trailer
    • Powered module connects directly to battery to avoid overloading vehicle's electrical system
  • Constructed using surface-mount technology (SMT) for consistent, reliable performance
    • Maximizes trailer light yield and intensity while producing minimal heat
    • Ensures superior operation in rough road conditions
  • Comes with dust cap for 4-way flat connector


  • Maximum amperage:
    • Stop/turn lights: 5 amps per circuit
    • Tail lights: 7.5 amps per circuit
  • Limited 1-year warranty


This custom-fit T-connector plugs into your vehicle's wiring harness, which is located behind the driver's-side and passenger's-side tail lights. You will have to remove the tail light assemblies 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.

Once installation is complete, the 4-way connector will be stowed beneath your vehicle, near the trailer hitch. A mounting bracket (sold separately) is recommended to keep the connection secure.

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.

Powered Tail Light Converter with Surface-Mount Technology

A tail light converter is built into this T-connector. This converter is a circuit-protected, battery-powered unit that bypasses the electrical routes that are used by a basic wiring harness. As a result, there is virtually no draw on your tail light circuits.

Because most trailers run on a two-wire system - wherein the brake and turn signals are carried on one wire - the separate brake and turn signals from your vehicle's three-wire system need to be combined so they are compatible with the wiring system of the trailer. This converter combines the brake and turn signal functions of your automobile so that they run on one wire to properly activate your trailer's tail lights. Note: This will not affect how the tail lights on your vehicle operate.

Curt builds each tail light converter using surface-mount technology (SMT). This method of construction involves soldering electronic components directly to the surface of a printed circuit board. SMT eliminates the need for leads, which are used in older through-hole technology. The result is a circuit board that is smaller yet provides more routing area and that offers superior performance, reliability and durability.

Curt SMT Circuit Boards

Circuit boards constructed using SMT have been shown to perform better under rough conditions with excessive vibration than those made using the through-hole method. And where would vibration be more likely to occur than in towing applications? Curt converters also produce less heat, leading to increased durability and longer life. In addition, lower levels of resistance ensure better performance, especially for parts that operate at higher frequencies.

Each Curt circuit board is made using high-quality components that are pieced together in the most technologically savvy fashion, leading to greater predictability and reliability in functioning.

56436 CURT T-Connector Vehicle Wiring Harness with 4 Pole Trailer Connector

Installation Details C89FR Installation instructions

This Product Fits The Following Vehicles

Video of Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Curt T-Connector Vehicle Wiring Harness Installation - 2019 Ford Edge

Hey everybody. It's Rob here at etrailer.com. Today, we've been taking a look at the CURT T-connector vehicle wiring harness on our 2019 Ford Edge. Now our CURT harness is going to provide us with a four-pole flat trailer connector. That way, whenever we're towing a trailer, you're going to have all the required lights to get down the road safely, like our stoplights, our taillights, and our turn signals. And the other nice thing about it is, that a four-pole connector is going to be one of the most common trailer connectors out there, and it is going to be adaptable so we can use other ones, if you have other ones on your trailer, like a five, six, or even a seven one.

Now, our wiring is designed to stay on the outside of the vehicle. That way it's really easy to access and we can have it to hook up whenever we're hooking up to our trailer.Now it is going to come with a dust cover to help keep all that dirt, debris and moisture out. But one thing I do want to mention is, we have ours mounted into this bracket, and it's not going to come with the bracket. You can use your dust cover to just attach it to your hitch here, but I always think it looks a little nicer and it just protects the wires a little bit better because they're going to be securely mounted and not hanging down. And what I really like about our wiring is that it has a converter box and it's going to take the signal from our Edge and transfer it to a working signal for our trailer.

But it's also going to make sure that our wiring is protected when we got back-feeding. So there's a problem on your trailer, but you have a short circuit or something. It's not going to back-feed into our Edge causing any kind of damage like that.I know another thing a lot of people worry about is wiring in general, people get a little bit nervous when it comes to the installation, but that's the nice thing about the CURT. There's no cutting or splicing of the factory wires at all. It's a simple, T-connector that's just going to plug in line with your tail lights so they can get the signal out to the trailer, but also out to the taillights.

And we are going to have to run a wire up to the battery so it can get power for the converter, but it's also going to have a fuse to make sure that that's protected as well. So it's really going to make sure that no matter what happens on either end, we're not going to have to worry about any kind of damage to the system on our Edge.But now that we've seen what our wiring looks like and gone over some of the features, let's go through the installation process together. So you can have the confidence to do it at home. To begin our installation. We want to open up our rear hat on our Edge and we're going to come right to the insight channel here, right next to our taillight.

There's a little plastic clip, that's covering up the mounting holes and the hardware that's holding it in. So you just want to grab a screwdriver and we can pop it out. Just get your screwdriver, work into the Edge. I'm going to pull that little plastic panel out, and then inside of there will be our screw that's holding it in, so you want to use a T 25 Torx bit to take it out.You want to be careful trying not to drop this screw. We'll pull it out. Then we can pull our taillight out. Now, whenever you go to take it out, you don't want to twist it too much, because a lot of our taillight actually goes on the side of our Edge here. So we want to pull straight back as much as we can. It is a little bit difficult to kind of get grab on anything, but you do not want to try to pry on the corner here because it is very thin plastic and we don't want to break it.So if you typically can grab right her and again, just pull straight back because on the back of the taillight, we have these pins, and again, we don't want to break them. Once we have them out, we can grab our connector here. There's a small tab. We're going to push in on that tab and lift straight up. Pull the tail light out. We'll move to the other side and repeat that and make sure we put our taillights where they won't get damaged. Then we have our taillights out. We need to get our wiring harness up to the taillight pocket. But if you look, there's really not a whole lot of room between our facia and the body here. So you went to grab yourself a plastic trim panel tool, and if we look along the top here, the outer edge of our facia is just clipped in by a few clips.So you just want to loosen them up and just kind of pull upwards on the facia. Or if you need to, you can take that plastic trim panel tool kind of come underneath those clips, just so they're a little bit loosened up, and then right in this section, right behind the facia, there's actually a push pin that's holding it in against the body. So then you're going to, you can either use your plastic trim panel tool, or you can get a trim panel tool like this and come in behind that push pin, work it loose, and that'll give us just enough flex so that we can get our facia pulled away right here at the corner, and we can get our wiring up to the taillight pocket here. I'm going to be using the fish wire method to get my harness up to the top here.Now I'm going to use an airline tube, but you can use just about whatever you have. You don't have an airline tube, you can use a coat hanger or even a string with something heavy tied to it, so it can fall down to the bottom of the bumper here. We'll just pass our fish wire down in between the facia and the body until we can meet up at the bottom of the bumper and get access to it. I just want to make sure that your pull wires long enough, that it will go all the way down. Since we have some appearance panels down here, you may need to reach up, find the wire and pull it out, but it should come out pretty much right underneath the taillight at the very bottom of the bumper. I'm going to grab my harness and I'm going to take the yellow end connector to the end of here, and we can pull it all the way up and, we have enough room to get them pulled up into the taillight pocket here.We can go ahead and remove our pull wire and the tape. Just line the connectors up, plug it in. We should be able to just kind of tuck the wire away and then be able to get this connector in place and get the taillight in place. It's just, it's a very tight fit. So you may have to move your connector and wires around to get it back in. We'll just take our connector, plug it in, make sure it locks in place. Give it a quick tug. And again, we're going to have to find a way to tuck our wiring out of the way to make sure that we can actually get everything in. So I'm just going to put that clip back in, make sure that it's not going to interfere and I'm going to tuck my connector probably right in between the body here next to the facia.It might fit if it put it just like this, but again, we just kind of have to test to see if it's going to be in the way, but now that we know it fits, we can go and put that screw back in, and this side on this taillight, at least, we'll be connected. So now we want to take our green wire with the T-connector on it, and we want to route this over to the passenger side. We're going to use that same method to get the wire up and connect it. You do just want to be very mindful of your exhaust as you're passing it over, because we don't want to have anything too hot or anything that potentially may damage the wire. So as I route this over, I'm actually going to go over the top of the bumper beam right here and run it all the way across, and to help me get that over to the other side, I'm going to use an airline tube again and use that as my pull wire.So I'll get it started by going over the frame, making sure I clear everything, get it up as high as I can, and then I'm going to feed my airline tube so I can get access on the passenger side. Let's tape our connector for our pull wire, we're going to pull all that slack through and then pull it up to the top. We have most of the slack through, you can either run your airline tube down from the top where if you have a long enough one, you're already down here, just watch the exhaust that you can run your wire up and then go back up top and pull that slack through. On this side, you do want to make sure you pull all the slack up because we don't want our wiring to fall down and land on the exhaust. We're going to take our tape off and we're going to hook it directly to our taillight, just like the other side. And then we can reinstall our taillight back here on the passenger side.I just took a couple of zip ties and I attached them together and actually went around this plastic piece. That way it'll have just a little bit of tension on it, and pull all the slack up. We can cinch it down and we'll have a little bit of tension keeping it from falling down. We're going to plug our connector in, tuck all our excess wire kind of down in between the body.We can put our taillight back in place. So you should have your converter box and a few other wires on the driver's side of your Edge still. We want to pay attention to our black wire first, this is going to be our power wire. It needs to run up to the battery. Now, obviously this length of wire is not going to reach, and that's why they provide you with a length of 12 gauge wire. So we want to grab the butt connector out of our kit, slide it over the end of our stripped wire and crimp it in place. We're going to grab the length of wire and strip back a little bit of the insulation. We'll crimp it into our butt connector home. We want to bring our attention to the converter box. We need to mount this somewhere securely, where it's not going to be rattling around and it's going to be somewhat protected from the road spray.Now we do have this panel right here, so it should be protected if we put it up kind of high. We do have an eyelet on our converter box, but they also give you a foam sticky pad that you can stick it to a nice flat surface. So, that's what I'm going to do. I'm going to clean off the converter box and the surface, and then we'll stick it somewhere in this area so we can make sure it's nice and protected. Next, we can start with our white wire that has a ring terminal. This is going to be our ground, and you can see, we have plenty of slack here. So I'm actually going to route this a little bit away from the exhaust, we're just going to find a flat piece of sheet metal that we can take the self-tapping screw and we to secure it down. I am going to route it behind this panel here, and then just come forward to that panel and grab our wire, pull it out.I'm actually going to go up, so it will be nice and protected underneath this panel here. I'm going to go up and I'm actually going to attach them to stretch my wire out. So I don't have to worry about that slack coming down and I'm going to attach it right in the center, right in front of our muffler, right about where the sub frame is. Okay, So we should have two wires left one with our four-pole connector, and our power wire. Our four-pole connector, you just want to route towards the center by your hitch. We have a four-pole mounting bracket so we can have a nice clean look, and it will keep our wiring secure.But we're going to go ahead and route that after we get our power wire up to the battery, and when you are running your wire, you just want to stay away from any major heat sources like the exhaust, any moving parts, like the steering or suspension, and just make sure you use as many zip ties as you feel comfortable, and that your wire is secure. I'm going to run this up to the battery and then I'll show you the path that I took.So I started running my wire towards the front or behind this appearance panel, and I actually sent my wire over the rear sub-frame and axle, went over all of these braces coming down underneath these panels, and you actually see the wire right here, went around my fuel tank, and we actually had the big panel that's going to have a lot of protection for our wire. So you just followed it all the way down until it comes out to the end of the panel. Now, I already went ahead and dropped my airline tube down as my pull wire and went ahead and attached the excess wire. So now we can go up top and pull it up. But again, as you're routing your airline tube, you want to watch because our exhaust is right here. So if you can, try to use the lines or anything that's over towards this side to try to keep your wire away from the exhaust as you pull it up.I have my airline tube pretty close to the firewall. Fortunately, the battery's right there, but once you get your wire up, you do want to pull all the slack up, and it's not a bad idea to double check underneath, make sure there's not a wad of wire, cause we don't want it to get caught on something and rip out as we're driving down the road. It's also not a bad idea to anchor it to something as I'm probably going to use a zip tie to tie it right to this wire loom right here,, and we don't have to worry about the wire falling down landing of the exhaust, or again, catching on anything while we're driving. So we're going to build our fuse holder now. Now it's going to have a one continuous loop of wire. So I just want to make sure you cut it in half, and we're going to strip back both ends.On one end your going to take the ring terminal that comes in your kit, and crimp it down the other open end, we're going to grab another yellow butt connector out of our kit and crimp it in place. We can come back to our power wire now, and since we're so close to the battery, we can actually just trim off just very slightly ahead of it. So we have some wire to work with and we can get rid of the excess, go ahead and strip back the end of our wire.This is going to go right into the other end of that butt connector, and we want to take off the nut that's on the positive post of our battery. So we'll be using a 10 millimeter socket to listen to them. We're going to take our ring terminal, you do want to make sure your fuse is not in the fuse holder at this point, we'll slide our ring terminal over. We can reinstall and tighten down the nuts.Then we can put the fuse in. We can make sure that our circuits are working properly, and once we do that, it'd be a good time to clean up any excess wires. Make sure you manage your four- pole and just tidy everything up for a clean look. I'm going to go in and plug in my four-pole tester or run through the lights and verify that they're all working properly. So if I turn on my headlights, we can see that our taillight function is working our left turn signal, our right turn signal, our brakes ,and the brakes and both turn signals. All we have left to do now is hook up to our trailer and hit the road. But again, I'm Rob here at etrailer.com. That'll finish up your look at the CURT T-connector vehicle wiring harness on our 2019 Ford Edge..

Customer Reviews

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - C89FR

Average Customer Rating:  4.5 out of 5 stars   (4 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring. Powered converter reduces strain on wiring system and is made using SMT to ensure superior performance.

- C89FR

Easy plug and play once I got the taillights off. All wires fit inside the left taillight housing. Biggest issue was running the power wire to the front to the battery.

- C89FR

everything came as ordered if I had any complaint it would be the wire connectors I feel they should be a heat shrink type. I replaced mine with heat shrink type connectors there for four stars instead of five.

- C89FR
2019 Ford Edge

- C89FR


Ask the Experts about this Curt Custom Fit Vehicle Wiring

  • Which Curt Wiring Harness for a 2020 Ford Edge SE or SEL
    The # C89FR has the manufacturer's part number 56436, which is the CURT T-Connector Vehicle Wiring Harness with 4 Pole Trailer Connector. This harness is a confirmed fit on your 2020 Ford Edge as long as you have either the SE or SEL trim package. I've also linked the installation video of this part for you to check out, as well.
    view full answer...
  • Can Curt Dual Hitch Adapter Be Used with Subaru Outback to Carry E-Bikes and Tow Trailer
    The Curt hitch part # C89FR that you have installed on your Outback has a higher tongue weight capacity so what you are looking to do with the Curt dual ball mount # D210 could possibly work. You should note that when you use the # D210 with a bike rack in the upper hitch opening you cut the capacity of the hitch by 50 percent so with the Curt hitch you have you'd be limited to 300 lbs of tongue weight for the trailer and you e-bikes. Then for a bike rack the Thule EasyFold XT part...
    view full answer...
  • Trailer Wiring Harness That Fits 2019 Ford Edge
    You are correct, the Curt T-Connector Vehicle Wiring Harness # C56272 is not a fit for a 2019 Ford Edge; this harness is only a fit for 2015-2018 Ford Edge SE and SEL models; whoever told you it did fit your vehicle was mistaken. We carry the correct wiring harness for your 2019 Ford Edge, depending on the model. - 2019 Ford Edge SE or SEL: Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C89FR - 2019 Ford Edge Titanium: Curt T-Connector Vehicle Wiring...
    view full answer...
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  • Parts Needed to Use a Curt Echo Brake Controller With a 2021 Ford Edge SEL
    You can still go with the Curt Echo # C51180, even with your phone handling all those functions. Though you will need your phone for the initial set up, you can then use the Manual Override Button # C83HR. Manual override is the only function the phone will handle after getting everything set up and running properly. I can say that your 2021 Ford Edge will not have a brake controller fuse, so you may need a few parts to get the controller the needed power, depending on what you have...
    view full answer...

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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jeff D
Installed by:
Jeff D
Employee Jameson C
Expert Research:
Jameson C
Employee Dustin K
Video Edited:
Dustin K
Employee Wilson B
Updated by:
Wilson B
Employee Robert C
Test Fit:
Robert C
Employee Kristina F
Written by:
Kristina F
Employee Michael B
Video by:
Michael B

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