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25 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire

25 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire

Item # A25W5B
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Trailer Wiring
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A25W5B - 5 Flat Optronics Trailer Connectors
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5-Way trailer harness connects to your tow vehicle to control trailer light functions. Wishbone-style harness comes with 2 tail light wires split for simple wiring. Auxiliary wire signals trailer brakes to disengage when in reverse. Lowest Prices for the best trailer wiring from Optronics. 25 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire part number A25W5B can be ordered online at or call 1-833-496-1390 for expert service.
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Optronics Trailer Wiring - A25W5B

  • Trailer Connectors
  • Trailer End Connector
  • 5 Flat
  • Plug and Lead
  • 21 - 30 Feet Long
  • Optronics

5-Way trailer harness connects to your tow vehicle to control trailer light functions. Wishbone-style harness comes with 2 tail light wires split for simple wiring. Auxiliary wire signals trailer brakes to disengage when in reverse.


  • 5-Way trailer harness connects to your tow vehicle to control trailer light functions
    • Ideal for marine trailers with hydraulic or surge brakes
  • Wishbone-style harness comes with 2 tail light wires split for simple wiring
    • Allows you to run wires separately down each side of the trailer to tail lights without needing a jumper wire
  • Auxiliary wire (blue) connects to backup light circuit to disengage surge brakes when you are driving in reverse
    • Hydraulic actuator must have electric lockout feature built-in to disengage the trailer brakes
  • Color coded wires help with installation
    • White - ground
    • Brown - tail lights
    • Yellow - driver side stop/turn
    • Green - passenger side stop/turn
    • Blue - auxiliary wire


  • Wire harness length: 25'
  • Wire gauge (all): 20
  • Ground wire length: 30"
  • Auxiliary wire length: 5'

Manufacturer Cross Reference
Harness will work as an exact replacement for:

  • Truck Lite # 002275

A25W5B Optronics 25 Ft 5-Way Trailer End Wishbone Wiring Harness - 30" Ground - 5' Blue Wire

Alternate part number: A-25W5B

California residents: click here

Customer Satisfaction Score:

Customer Reviews

25 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire - A25W5B

Average Customer Rating:  4.7 out of 5 stars   (39 Customer Reviews)

5-Way trailer harness connects to your tow vehicle to control trailer light functions. Wishbone-style harness comes with 2 tail light wires split for simple wiring. Auxiliary wire signals trailer brakes to disengage when in reverse.


After having this in my garage for about 6-9 months I finally got around to rewiring my trailer with this harness. The harness has been on the trailer for 4 months and it has been solid. I would recommend getting longer than you think you will need. IE if you have a 25 ft trailer get a harness that is ~30 ft.


I have been in sales, retail, B2B, and sales management for over 30 years. E trailer has the whole package - excellent customer and sales service, great products, videos for those of us who like to do our own work, fair prices, and my go-to for my trailer needs.


So, I converted my brand new Loadrite trailer to LED'S and wanted to add up a reverse light. I purchased this 5 wires trailer light harness to do the trick. Very good quality and the color code stayed the same. Had no problem what so ever and was an easy swap. I soldered every wires and protect them with heat shrink tubing and that should last a very long time.
Thank you.

George, after one year, Im pleased to say that your product still perform flawlessly. All is good with the harness and would recommended to all of your potential customer. Thank you for the follow up a year later, really show whos taking care of his customer. Again, thank you,
Vincent - 05/19/2019


I. ordered this along with marker lights its been a year and they work great.


Easy to install perfect length and works great!! Can’t see it on the trailer because I have it heat shrinked and wire loomed for protection


I purchased this set to rewire my race car trailer and add reverse lights to the pigtail... wiring went flawlessly and there was plenty of wire and connectors are good quality... even had a dog chew on the trailer end and other than a slight ground issue, works perfectly.


This product was exactly what I was looking for. I was having issues with my trailer lights on a 20 year old trailer. I decided it was best to just remove all of the old wiring and start off new. This product took care of any concerns i might have had by just replacing a wire or two. All of the lights and connections are excellent and I don't worry about something not working.


Package arrived late Fri night or Sat morning which isn’t bad but I don’t know what your processing time is. I never got a confirmation that it had shipped. Everything came in good shape and was installed on trailer. I would use your company again. Thank you for responding to me.


Got this wiring harness for my small camper to completely re wire it. Also got rheTLl28RK combination trailer lights. Nice and bright!


5-wire harness kit is exactly what I need. I hate splicing wiring runs because, in a saltwater environment, this only leads to more chances for corrosion. The only thing that would be better is the complete round plug set-up.
My boat and truck are happy!


Wiring is great. Was given 2 truck tail lights with back up lenses so I needed to rewire my trailer for a 5 wire system. My trailer is 30 years old so it needed a complete makeover. e trailer was a great help. They had a 5 wiring harness and a duel trailer connector for my Jeep. I needed a 4 wire and a 5 wire adapter to fit the Jeep to 2 trailers I own. They had what I wanted and it was delivered in 3 days.


This wiring is almost plug and play! It is already set up with double brown wires to meet today's trailer wiring standard. And with the hitch-end flat plug and ground ring already in place, it is a quick installation. Thanks.


Needed to replace my wiring on my 18 foot boat trailer. This did the job. Easy plug and play.


Great, I think I will enjoy the install, with all that's going on in the World. Thanks for the extremely fast delivery and help with making my selections!

I did make one mistake, the Thin LED Light I order; I think I need to order the base bracket as well!


Fast shipping and great product. Easy to install on my boat trailer. Will test the longevity of this product over the next several years. But overall very pleased, and etrailer is a wonderful company.


Great customer service and fast shippin g!


When the original products I ordered was out of stock, they contacted me ASAP and let me know there was another part number that could be used. Great service.


Product works well. Installed on boat trailer used primarily in saltwater. Corrosion is minimal.


I received exactly what I thought I needed. I have my trailer rewired and we're ready to go fishing. Couldn't be happier!


Had to run my own ground wire down both sides in order to complete installation


Well made product easy to install.Delivered in 3 days,with free shipping as I ordered it with a few other items.Priced very reasonable. I am very happy with my order.


All products are good quality and arrived in just a few days! Excellent service!


Wire harness arrived quickly and was exactly as described. Worked perfectly and great price.


Good quality product. Worked perfectly for me. Thanks!


Part was not in stock but company stayed in close communication until I received my order. Very pleased with this company in other orders as well.

Show More Reviews

See what our Experts say about this Optronics Trailer Wiring

  • Trailer Ground Troubleshooting that is Affecting all Trailer Light Circuits
    What you are describing sounds like the typical bizarre behavior of a ground problem. Since it seems to be affecting all of the circuits I would start with the connector on your trailer. I would check the ground circuit for corrosion and fix as necessary. If that does not fix the problem you could try checking all of the grounds of your trailer and make sure they are attached to a clean metal surface. You might even try running a jumper cable from your ground circuit to the frame of your...
    view full answer...
  • How To Disconnect Wiring Harness On Boat Trailer Before Launching And Still Use Reverse Solenoid
    What you will want to do is keep the wiring harness connected until you have backed the boat trailer on the boat ramp. Then, with the boat trailer on the boat ramp and it sloping down towards the water you can unhook your wiring harness. That way the weight of the boat is pulling down the hill and will keep the brakes from locking up since it is going downhill. Also, you will not want to connect the wiring harness to the boat trailer as soon as it is pulled out of the water. Let the trailer...
    view full answer...
  • 5-Way Replacement Recommendation with Wishboned Trailer Running Light and Ground Circuit
    The closest matching 5-way replacement we have uses a single wire for the ground but has the wishboned running lights like you need, part # A25W5B. You'd have to run both of your trailer ground wires to the single ground wire and you'd be fine.
    view full answer...
  • Troubleshooting Trailer Lighting That Blinks when Headlights are On
    Since all the lights are blinking and it's only happening when the headlights are on the issue has to be related to the running light circuit of your trailer wiring. Most likely you have an intermittent connection here due to corrosion on the trailer wiring connectors and cleaning them will take care of the problem. The other possibility is that you have a weak ground on your trailer wiring. An insufficient ground can sometimes cause unexplainable behavior on trailer taillights. You would...
    view full answer...
  • Troubleshooting Trailer Wiring that Turn Signals Cause all Lights to Flash
    Sounds like your trailer connectors are miss-wired or are shorting out. What you will first want to do is use a circuit tester like the part # 3808 to test the pins of the trailer connector on your truck for voltage in the correct places. Since I don't know what style of connector you have on your truck you will need to check out the help article I attached that has diagrams for all common trailer connectors. If the problem is on the trailer you will need to rewire the connector of the...
    view full answer...
  • Is the 25 ft. Wishbone 5-Way Trailer Harness Compatible with LED Taillights
    Yes, the 25 foot 5-way harness part # A25W5B that you referenced is perfectly compatible with LED taillights.
    view full answer...
  • What is the Wire Gauge Size of the Blue Wire on the Optronics Wishbone 5-Way Trailer Harness
    The blue wire on the Optronics 25ft Wishbone 5-Way Trailer Harness, # A25W5B, is a 20 gauge wire.
    view full answer...
  • Trailer Lights Come On and Stay On Bright
    It sounds like there is a short somewhere that you will need to track down and correct. A short would cause constant power draw and could explain why the lights come on and stay on. Make sure the vehicle and trailer side connectors are clean and free of corrosion. Inspect the wiring from the front to the back and look for any frayed, pinched, or damaged wire and repair as needed. I have included a couple of helpful links on testing and troubleshooting wiring for you.
    view full answer...
  • Turn Signal on Trailer Stops Working when Headlights are On
    The problem you are having is a classic ground issue. If the ground wire to the trailer frame or the tail light grounds are not connected securely to clean, rust and paint free surfaces then when the headlights are turned the extra amperage draw for the running lights will cause all sorts of lighting issues. I would start by removing the ground wire at the trailer coupler and cleaning up the connection point and re-securing it to the trailer frame. Next I would check the ground connection...
    view full answer...
  • What Gauge are the Wires on Optronics Wishbone 5-Way Trailer Harness?
    The 25-foot Wishbone 5-Way Trailer Harness # A25W5B has 20 gauge wires. I have added a link to a video review of this product for you to take a look at.
    view full answer...
  • Replacing 5-Way of Trailer that Has Two White and Brown Wires
    What you have is a wishbone style of 5-way that has the ground and running light circuit split for either side of the trailer. You can replace this setup with one that has a single wire by running both of the wires on the trailer side to the new connector if you wanted. We have the part # A25W5B which has the ground circuit wishboned but you'd need to run the two wires to the single running light circuit.
    view full answer...
  • Why Does Trailer 5-Way part # A25W5B Have 6 Wires
    There are 6 wires on the 25 Ft 5-Way Trailer Wiring Harness # A25W5B that you referenced because this has a wishboned running light circuit which means it has a wire to run to either side of the trailer's running light circuit. So it still has the 5 standard circuit of a 5-way but just has two wires you can use for the running light circuit.
    view full answer...
  • Wishbone Trailer Wiring Harness for a Magic Tilt Boat Trailer
    I believe you have what is referred to as a wishbone wiring harness. A wishbone wiring harness has 6 wires and is the same as a 4-way for the exception that it has both running light wires ran to the trailer connectors as opposed to splicing them together and then running them to the trailer connector. The functions should be as follows: Green - Right Turn/Brake Yellow - Left Turn/Brake Yellow/Brown - Left Running Light Green/Brown - Right Running Light White - Ground Red - Reverse Lockout...
    view full answer...
  • Replacement Trailer Wiring Harness For a Boat Trailer Using a 5-Way Flat Connector
    Currently the only wiring harnesses we have with a 5-way flat connector are like the 25 Ft 5-Way Trailer Wiring Harness # A25W5B and 40 FT Harness # A40W5B. These harnesses use 6 wires coming from the connector. It has a short 5' blue wire to run to the surge brake electric lockout, a short 30" ground wire to attach to the trailer frame, 2 brown wires for the running lights on either side of the trailer, a green wire for the passenger brake/turn signal and a yellow wire for the drivers...
    view full answer...
  • Replacing Trailer 5-Way Connector That has 7 Wires
    What you have is a 5-way with a double wishbone, which means it is likely a double wire for marker lights as well as a double ground. You can replace your 5-way with another wishbone-style but it does not need to be a double wishbone with 7 wires, you can replace it with a standard 5-way wishbone with 6 wires. There are a couple options depending on the length you need: - 25 feet: 5-Way Trailer Wiring Harness - Wishbone Style # A25W5B - 40 feet: Wesbar 5-Pole Flat Connector - Wishbone...
    view full answer...
    Image 1 for
  • Recommended Way To Protect Wires On Trailer Wiring Harness
    The only sort of protection we offer for wire leads such as those on the 25 Ft 5-Way Trailer Wiring Harness part # A25W5B would be wire loom, the 3/8" Diameter Wire Loom part # 39035. This can be used to cover the length of wire on the tongue or anywhere else for that matter to help protect from rodents.
    view full answer...
  • Replacement 5-Way Recommendation to Replace a 5-Way that Had 7-Wires Run to It
    What you have is a 5-way trailer connector with a wishbone running light circuit and 5th auxiliary circuit. The closest thing we have would be the Wishbone 5-way Part # A25W5B. This has a wishboned running light circuit, but the 5th circuit is not. You can still make this work though. You just need to run both of the red wires from your trailer wiring into one butt connector and then run the other side of the butt connector to the blue wire of the # A25WB.
    view full answer...
    Image 1 for
  • 5-Way Connector Recommendation for a Boat Trailer for Reverse Lights
    An exact adapter like what you are looking for doesn't exist, but I do have a better solution for you. You would want to cut off the 4-way on your boat trailer and then replace it with a 5-way like part # A25W5B. You would want to cut all but the blue wire short with this connector and then match it up to the 4-way wiring you have on your trailer. With the blue wire left long you could run it to the reverse lights on the trailer.
    view full answer...
  • New 5-Way Trailer Side Connector for a Boat Trailer
    Your trailer has a type of wishbone harness with separate wires that share the running light circuit. For a replacement I recommend # A25W5B. The one covered pin is the ground, next to it is the running light pin. There are 2 wires associated with this pin. One goes to the trailer left side running lights the other goes to the trailer right side running lights. The next two pins are left turn/brake lights and right turn/brake lights. And the last pin and wire go to the electric reverse...
    view full answer...
  • Parts Needed to Wire a 5-Way to a Boat Trailer
    The best solution is going to be the part # A25W5B. What you would want to do is use the part # A25W5B to provide the wiring and connector for your trailer but then use a junction box like part # 38656 to make organizing the wiring and running each of the wires to each circuit easier. I attached an install video for this box for you to check out as well. I also attached a help article with trailer wiring diagrams as well.
    view full answer...
  • 5-Way Trailer Wiring Harness that Has Wishboned Running Light Circuit
    We do have the 25 Ft 5-Way Trailer Wiring Harness # A25W5B which is a wishbone style of 5-way like you are in need of.
    view full answer...
  • 5-Way Wiring Harness Availability for Tent Trailer
    Yes we do. For a 5-way plus 25 feet of wiring you would want the part # A25W5B. In case you need the vehicle side too you would want the part # 20016.
    view full answer...
  • Replacement 5-Way Flat Trailer Connector Recommendation
    The 25 Ft 5-Way Trailer Wiring Harness part # A25W5B will do the trick for you. It is a bit longer than you need but the 4 male and 1 female plug is usually found on the trailer and not the truck causing the long harness issue. Typically you find this on the the vehicle side of things. Hopkins Wiring Harness with 5-Pole Flat Trailer Connector - Vehicle End - 5' Long part # HM37908 this would meet your requirements but you would have to change the trailer side to the harness listed above...
    view full answer...
  • Trailer Wiring Issues with Running Lights Blinking
    Step one is to isolate the problem to either your tow vehicle, your wiring harness or your trailer wiring. To begin, disconnect the trailer wiring harness from the towing vehicle. First focus on troubleshooting the trailer. Check the white ground wire from the trailer plug to ensure that you have a clean secure ground connection to the trailer frame. Internal trailer wiring can over time develop wear spots in the insulation that can create a dead short. Such a condition will quickly damage...
    view full answer...

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