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Mighty Cord 4-Way Flat Trailer Connector - Wishbone Style - Trailer End - 25' Long

Mighty Cord 4-Way Flat Trailer Connector - Wishbone Style - Trailer End - 25' Long

Item # A10-4225VP
Our Price: $19.45
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Custom Fit Vehicle Wiring
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A10-4225VP - Custom Fit Mighty Cord Trailer Hitch Wiring
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Splice this wishbone-style harness into your trailer's wiring to power each of the side lights. Split brown wires make installation easy. 4-Way flat connector plugs into the 4-way flat on your tow vehicle. 1-800-940-8924 to order Mighty Cord custom fit vehicle wiring part number A10-4225VP or order online at Free expert support on all Mighty Cord products. Great prices and Fastest Shipping for Mighty Cord 4-Way Flat Trailer Connector - Wishbone Style - Trailer End - 25' Long. Custom Fit Vehicle Wiring reviews from real customers.
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  • Reviews (38)
  • Q & A (0)
  • Videos (2)
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  • Why etrailer?

Mighty Cord Custom Fit Vehicle Wiring - A10-4225VP

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • No Converter
  • Mighty Cord
  • 25 Feet Long

Splice this wishbone-style harness into your trailer's wiring to power each of the side lights. Split brown wires make installation easy. 4-Way flat connector plugs into the 4-way flat on your tow vehicle.


  • 4-Way flat trailer-end connector plugs into the 4-way flat on your vehicle
    • Syncs your trailer's brake lights and turn signals with your tow vehicle's
  • Wishbone-style harness has split wiring for each tail light
    • Run wires separately down each side of the trailer without the need for a jumper wire
  • Durable molded rubber protects the wires from moisture and debris
  • Simple installation - hardwires to existing trailer wiring


  • Harness length: 25'
  • Wire gauge: 20 AWG
  • Wiring configuration:
    • Green: passenger side brakes/turn signal
    • Yellow: driver side brakes/turn signal
    • Brown: tail lights
    • White: ground
  • 1-Year warranty

A10-4225VP Mighty Cord 4-Pole Wishbone Plug - Trailer End - 25' Harness

California residents: click here

Video of Mighty Cord 4-Way Flat Trailer Connector - Wishbone Style - Trailer End - 25' Long

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

Video Transcript for Mighty Cord Wishbone 4-Way Flat Trailer Connector Review

Jake: Hey guys. Jake here at etrailer. Today we're going to be taking a look at and I'm going to show you how to install this Mighty Cord 25 foot four pole wiring harness. Today we're going to be doing it on a boat trailer, but for any of your four-pole applications, this is gonna be a great kit.This is going to work great for our trailer here, because we have a 24 foot trailer, so that gives us an extra foot to be able to have it sticking out to go into our floor pole. This wiring harness is going to differ a little bit from your standard four pole. This one is going to have your ground wire, your right and left turn signal wires, and then two brown power wires.

Those brown power wires are gonna come in handy when you have side marker lights like we have here. We'll show you how to get those connected later on, but it's also going to help to power your tail lights.When you're thinking about rewiring your trailer, whether you just have old wire or if you have a broken wire, you might want to go ahead and check your lights to make sure they're in good working condition because if they're not, it might be a good idea to switch over to LEDs. We have factory LEDs on this trailer, so we just went ahead and reused them. If you need LED lights, we have plenty here at etrailer.This wiring harness is going to have a wishbone design, which means it's gonna have that brown wire that goes one to each rear tail light, which is going to be a nice benefit because otherwise you'd have to run your right or left rear tail light over to the other side of the trailer once you get the wire run to the back, and then splice into the brown power wire to get it over to the other light. On the end you're going to have your standard four-pole.

That's going to accommodate to plug into your four-pole on your vehicle.Now that we've talked a little bit about the kit itself, let's go ahead and show you how we got it installed. To start our installation, you're going to need to find where your wires are run and run them in the same place as your old wires. Here we already have our wires run, but it's going to come in a little roll like this so you're going to need to unravel it and take it back to the back of your trailer just to be sure that you have the right length. This is what your wiring harness is going to consist of. The green and the brown are going to go to the back right tail light.

The yellow and the brown are gonna go to your left rear tail light. And then you're going to have a brown wire to be able to ground it to your trailer.On your trailer, you're going to have to find the access hole of where your wires are coming out of. We found our wires in this access hole here and the one on the other side of the trailer. So what you want to do is you want to tape the new wire to the end of your old wire and then get the end of the wire at the end of your trailer and pull it through so that your new wire is all run through the tube. One tip to make sure you don't pull your new wire too far is I tied a little knot around our brake line here so that when we pull our wire out, we know when to stop.Since we have side marker lights, we're gonna have to reach through our frame here to grab our wire with this hook tool.

So we'll pull our wire through our access hole. Here, you can see we use a heat-shrink butt connector to splice our power wire from our side marker light into our brown wire. Here on the rear tail light, we need to take our brown wire and connect it to our black wire, and our red wire and connect it to our yellow wire.Here's our wires all connected up. We can take a heat gun and shrink these down. When you're heat shrinking your butt connectors, you want to make sure that you're not getting it too hot to burn any of the wires. Once you've wired the one side of the trailer, you want to go ahead and repeat the process for the other side.Now that we've got the other side wired up, we can go ahead and take our ground wire and put a ring terminal on the end so that we can ground it properly to our trailer. We'll need to take a self-tapping screw and run it through our ring terminal, and screw it into our trailer. Now we're going to take our tester box and test out our lights. We plugged it into our four-pole down here and we'll go ahead and test them out.Here we see our tail lights are working with our side markers, our left turn signal, our brake lights, and our right turn signal.To finish this wiring up, we're going to go ahead and wrap some wire loom around it just to give it a finished look. We do have this available here at etrailer. Now that we've got it all bundled up, that's going to do it for our installation and look at the Mighty Cord four-pole wiring harness.

Customer Satisfaction Score:

Customer Reviews

Mighty Cord 4-Way Flat Trailer Connector - Wishbone Style - Trailer End - 25' Long - A10-4225VP

Average Customer Rating:  4.9 out of 5 stars   (38 Customer Reviews)

Splice this wishbone-style harness into your trailer's wiring to power each of the side lights. Split brown wires make installation easy. 4-Way flat connector plugs into the 4-way flat on your tow vehicle.

by: 06/01/2021

Exactly what I needed to rewire a 20-year-old trailer that was starting to show it's age with inconsistent lighting performance and continuity issues. In addition to purchasing this lighting harness, I upgraded all my incandescent bulb side markers and taillights with LED units and complete rewired the trailer. etrailer had everything I needed in one place with excellent pricing and superb service. Everything is working great and I love the brightness and visibility of the LED lights.

Still working great after many towing miles and boat launches!
Mark S - 06/02/2022


Excellent product worked as advertised. Would purchase again.


I installed the 25 foot wishbone 4 way trailer harness on my restored 1969 boat trailer a year ago. It was easy to install. I tied the wires into two new side lights on each side of trailer and the tail lights. Everything worked and I would purchase again.


Got the wiring harness to make an extension to pull our trailer behind our camper with bikes and kayaks in. This worked great! I love etrailer!


Low quality wiring. You get what you pay for. Insulation does come off when separating wires. If you need separate runs, buy the wiring on separate spools. If just using this for a trailer that does not require splitting the wires up, you should be fine, but I don't anticipate the wiring lasting longer than a few years.


This is a great harness if your rewiring your boat trailer. Plenty long enough for a 14-16ft trailer. Fast shipping and couldn't be happier with trailer products.


Very professional service. Fast shipping. I was treated as if I was the only customer they had spending millions of dollars. I highly recommend them.


Rewired my trailer and this harness was just the ticket. Shipped fast, great condition.


I have completed wiring and all new lighting on my 1996 boat trailer, using etrailer! Their representatives are extremely knowledgeable about their products, with professional courtesy always!


Haven’t installed the kit yet but I don’t expect any issues. As always, though, I’m very happy with Great pricing and delivery as usual.


Quality product. Just what I needed to finish up my trailer project. Will order from etrailer again.


product arrived timely, a pain to install but this is not your fault. Works well and solved all the problems. Keeps me legal. I"ll continue to use your service and products. Thanks. All - stay safe.


Got this item to re-wire an old 18 foot utility trailer. Worked out just right. Very good value for the price.


This product included all of the parts that I needed. They were packaged nicely and very easy to look at the website. The items in this order are well-made and pretty heavy duty. We love etrailer.


Products were as ordered and as needed. Self rewire project went very well and has functioned flawlessly.


It works fine and I would reccomend it.


Great product. Fits perfectly. The installation video was very helpful.


Great product, Shipping was excellent, will definitely tell my friends if they are going to re wire their trailer order from E-Trailer


Received the product for my trailer and it is what I ordered. Put it on and it works great.


Very professional and customer centric company.....


Ryan - 10/03/2022


great quality its great


Excellent quality and works great.


Exactly what I ordered. Very easy process and a good product. Definitely will be using them again when I need something else. Shipping could be a little faster.


Super fast shipping, the web site is the best I've ever used!! You have all the options anyone would ever need at any price range. Will be reordering soon!! You make my life easier.


Show More Reviews

See what our Experts say about this Mighty Cord Custom Fit Vehicle Wiring

  • Wire Gauge Mighty Cord Wishbone 4-Way Flat Trailer Connector A10-4225VP
    All of the wires of the Harness part # A10-4225VP that you referenced are 20 gauge.
    view full answer...
  • Wire Gauge Mighty Cord Wishbone 4-Way Flat Trailer Connector A10-4225VP
    All of the wires of the Harness part # A10-4225VP that you referenced are 20 gauge.
    view full answer...
  • Wishbone 4-Way for Trailer that Has 7 Wires Ran to 4-Way
    The best solution we have is the wishbone 4-way harness part # A10-4225VP which is 25 feet long. This has two wires ran to the running light circuit (brown) like you mentioned which you can run to either side of the trailer like what you have now but only has the single ground wire which you can run to the trailer frame as well as to the other wires you have and you'd be set.
    view full answer...
  • How to Determine What Wires Connect on Trailer
    I can help you figure out how to determine how to hook up your connector, though you cannot use colors to determine the functions of trailer wiring (or any wiring) because there is no universal color code, as helpful as that might be. What you need to do is test the wires for function using a charged 12 volt battery and a jumper cable, applying 12 volts to each wire which is going to tell you what their functions are; that will allow you to hook up your new connector. I have added a link...
    view full answer...
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  • Recommended Universal Wiring Harness for Trailer and Vehicle
    Yes, you are correct the # A10-4225VP is a 25 foot length of wishbone 4-way wiring for the trailer with a trailer connector. A good universal harness for your vehicle is the # 119190KIT. The cost's of each item are listed on each page. I have linked both to this page for your purchasing convenience.
    view full answer...
  • Function of Brown Trailer Wires With Green and Yellow Tracers
    If you are referring to wire colors on a trailer, then usually a brown wire is for running lights. If your trailer has two brown wires, one with a green tracer and one with a yellow tracer, then these would typically be the running light wires for the right and left sides of the trailer, respectively. Some trailer harnesses such as the 25-foot Mighty Cord # A10-4225VP are what is called a "wishbone" harness, which has two running light wires to make it easier to make the connections on...
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  • Replacement Wishbone Trailer Connector To Replace 6-wire Connector
    Your trailer connector is considered a wishbone connector. A wishbone connector splits the running light circuit into two separate wires. Instead of a single brown wire carrying the running light circuit, you have a wire for running lights on the right side of the trailer and another wire for left side running lights. Then you have a wire carrying the left turn/brake light circuit, wire for right turn/brake light circuit and white wire for ground. Since your connector has 6 wires you probably...
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    Image 1 for
  • Adding Auxiliary Backup Lights and Bumper Switch.
    Yes you can absolutely tie into that 12 Volt power coming from your 7-pole trailer connector. As long as you aren't drawing a bunch of power through it for other uses they are generally rated up to 30 Amps. You will need to supply power to it in two ways if you want it to work by a switch and when you shift into reverse. For this make sure you put your switch on your power wire side instead of the normal ground side and connect the reverse wire in after the switch. This will allow yo...
    view full answer...
  • Installation of Optronics TLL12RK LED Trailer Taillights
    Although there isn't a plug and play harness available, wiring up the # TLL12RK taillights to a trailer harness like # A10-4225VP would be extremely easy, as you can see in the provided video where my buddy Jake shows how the harness is installed. The wiring pigtails included with the # TLL12RK would connect as follows: • Red wire on pigtail connects to green wire on right side, yellow wire on left side • Black wire on pigtail connects to brown wire on both sides • White wire grounds...
    view full answer...
  • Troubleshooting 4-Way Trailer Wiring Causing Blown Fuse Each Time Connected
    Different trailers can have slight differences in materials, and wiring function. Since this trailer blows the fuse in your vehicle every time it is connected, it sounds like there is a short to ground somewhere on your trailer. This bad connection can be anywhere from the trailer connector back, since other trailers work fine with your SUV. I recommend using a battery to test the wiring functions of your trailer when not connected to your vehicle. You can then use a tester like #...
    view full answer...
  • What Does Some Trailer Wiring Have 2 Brown Tail Light Wires
    Common 4-pole trailer wiring like # HM38138 uses one wire, the brown one, for the running lights on both sides of the trailer. Sometimes what is called a 'wishbone' harness is installed on the trailer and this simply uses two separate running light wires - brown with yellow for left and brown with green for right - to make it easier to connect to the trailer lights since that way no jumper wire will be needed to cross from one side to the other. Some examples of wishbone style 4-pole...
    view full answer...
    Image 1 for
  • Why Does 4-Pin Trailer Wiring Have 5 Wires
    Your 4-pin/5-wire wiring harness is what is called a "wishbone" type which simply means that there are two separate running light wires, one brown and one pink. This allows a separate running light wire for each side of the trailer which saves you having to run a jumper wire from one side of the trailer to the other. We offer lots of wiring items just like this, such as # A35W42B, # A20WB and # A10-4225VP, which happen to use two brown wires instead of one brown and one pink. The functions...
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    Image 1 for
  • Installing Reverse Lights on Trailer Using 7-Way Connector and Wishbone 4-Way Wiring Harness
    Using the Mighty Cord Wishbone 4-Way Flat Trailer Connector - Trailer End - 25' # A10-4225VP will give you the wiring for the tail lights on each side of your trailer giving you both the running light for each side and then the stop/turn function for each side. The ground wire will connect to your trailer frame on a bare metal to metal surface. Then when using the Mighty Cord 7-Way RV-Style Trailer Connector w/ Molded Cable - Trailer End - 10' Long # A10-7W10 or similar based on length,...
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    Image 1 for
  • Recommended Coupler for Custom Kayak Trailer
    For your small kayak trailer, I recommend the Fulton Fas-Lok Coupler # F222000301. This will give you a 2 inch ball compatibility along with the ability to use a 2 inch square bar that you'd need to obtain locally to give you the length you need. That size will fit a standard 2 inch receiver tube if that is what is on your trailer. If you need a 2-1/2 inch bar compatibility, then I recommend the coupler # CT-3002-Z. For a 3 inch bar compatibility, I recommend the # CT-3003-Z coupler....
    view full answer...
  • 4-Pole Wishbone Harness for Running Light Connection
    Connecting the brown running light wire in standard 4-pole wiring to both tail lights will require a jumper wire from one side of the trailer to the other, or you can install what's called a wishbone harness that has dual brown running light wires, one for each side of the trailer. We have several of these trailer-side 4-pole wishbones, such as 40-foot # A40W42B, 35-foot # A35W42B, 25-foot # A10-4225VP and 20-foot # A20WB. I do recommend using a wishbone harness instead of a spliced jumper...
    view full answer...
  • What I Need To Install LED Trailer Lights On A Tent Trailer
    I have the perfect way for you to install tailights on your tent trailer with everything you will need although it will not come in a kit.You will want to piece together a lighting assembly for your tent trailer with your exact specifications, which I have done for you. For a set of round, surface mounted, LED taillights, I recommend using the Transit Tail Light part # STL90RB. These taillights are 7" wide X 1-7/16" thick and will work well for you. We also have a similar set of running...
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  • How to Extend Short Ground Wire on 4-Pole Wishbone Harness
    Wishbone 4-pole harnesses like # A35W42B, # A20WB, # W002230 and # A10-4225VP usually do have a short ground wire because most trailer frames are steel and they conduct well enough that a ground wire attached near the tongue will provide sufficient ground even for lights mounted all the way at the back of the trailer. On the other hand if you have an aluminum frame trailer that does NOT conduct electricity nearly as well as a steel frame then you might need to extend that 2- or 3-foot...
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  • Replacement 4-Pole Trailer Connector for Utility Trailer with 5-Wire Wishbone Wiring Setup
    When a 4-pole (4-pin) flat trailer connector actually has 5 wires this simply means it is a 'wishbone' style connector with dual running light wires. These dual wires just make it easier to connect to the running lights on both sides of the trailer. Examples of such items are # A35W42B, # A20WB and # A10-4225VP. If your trailer wiring is still okay and you just need a new 4-pole plug to re-connect the leads from the trailer you can use Hopkins Endurance Quick-Fix Replacement 4-Way Flat...
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Info for this part was:

Employee Jackie C
Expert Research:
Jackie C
Employee Jameson C
Expert Research:
Jameson C
Employee Jeff D
Installed by:
Jeff D
Employee Jacob H
Installed by:
Jacob H
Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video by:
Chris R
Employee Mary E
Updated by:
Mary E
Employee Halie H
Updated by:
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Employee Amanda M
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