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35 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 42" Ground
Optronics

35 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 42" Ground

Part Number: A35W42B
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$24.25
Retail:$25.62
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Trailer Wiring
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4-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. Great Prices for the best trailer wiring from Optronics. 35 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 42" Ground part number A35W42B can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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Optronics Trailer Wiring - A35W42B

  • Trailer Connectors
  • Trailer End Connector
  • 4 Flat
  • Plug and Lead
  • 31 Feet and Longer
  • Optronics

4-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.


Features:

  • 4-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
    • Allows you to run wires separately down each side of the trailer to tail lights without needing a jumper wire
  • Color coded wires help with installation
    • White - ground
    • Brown - tail lights
    • Yellow - driver side stop/turn
    • Green - passenger side stop/turn


Specs:

  • Wire harness length: 35'
  • Ground wire length: 42"
  • 3-Year Warranty


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

  • Truck Lite # 108835
Wishbone Wiring Diagram


A35W42B Optronics 35 ft. Wishbone 4-Way Trailer Wiring Harness with 42" Ground Wire

Alternate part number: A-35W42B




California residents: click here


Customer Satisfaction Score:

Ratings & Reviews

4.8

829 reviews
4-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.

by:

Good wire



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good quality



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Very nice product



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What I wanted



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Easy to use



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Takes all the guesswork out of trailer rewiring



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Very good customer service andm fast shipping, very pleased



by:

Just what I wanted......right price and shipped quickly.



by:

Product as listed - good price - quick shipping



by:

such great service...great pricing...great products!!



by:

Great item just what i was needing and shipped sooner then was told.



by:

Excellent Quality Products. Just the parts I needed to do the job, Done right the first-time.



by:

This is exactly what I was looking for, but couldn't find at automotive stores. Unbelievably fast shipping! I ordered it on Monday, it arrived on Tuesday!!



by:

You won't find this product for a better price. Worked perfectly as described.



by:

all good. Good instructions, youtube films with installation guides and prompt delivery.

Good product range as well



by:

fast servicethe trailer light cable came in 2 days at Christmas time. I didn't expect it so soon. The right product at a good price. thx



by:

Order for wiring, round plug, and plug mounting bracket delivered very quickly and is exactly what I needed.

Have bought from etrailer.com in the past and always been well satisfied with their products and service.



by:

Hard to find wiring harness length beyond 25' at most online retailers. Thanks etrailer.com. Easy transaction and prompt delivery.



by:

E-100 bumper hitch fit perfect. It seems to be a pretty substantial hitch. I have not tow with it yet but it should work fine.

I have not worked with the wiring are connections yet but they seem like they will work just fine.



by:

Can't wait to use this on my trailer...typical wiring that you would expect for a trailer application. Sturdy connections from the wires to the plug.



by:

I bought this wiring harness to re-wire my 28' 1984 Shoreliner Boat trailer. It was too easy to install. The video/suggestions at etrailer.com worked out perfectly and the harness went through the conduit like it was the OEM harness.



by:

Trailer harness kitKatie, thanks for letting me know the package was delivered and sitting outside my garage door! Your shipping and tracking service is the best I've experienced on internet ordered items. And the kit length enabled me to overcome a few personal errors in repair, with excess wiring left over.

Thank you for a good product and great service.



by:

Great product for my home-built camper trailer. I was able to feed all the lights without splicing extra wire in. Fast shipping too! This harness saved me time and money and works great.



by:

Great ProductNice wiring kit, super easy to re-wire 20ft boat trailer, for the price of this kit with the wishbone aka extra brown wire makes wiring marker lights a breeze without having to splice



by:

I received the wiring harness in soon after ordering it and it was what we needed to rewire our trailer. I was quite pleased. The length allowed for rewiring clearance lights and tail/brake lights, ;lus providing a good ground.


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Show More Reviews

See what our Experts say about this Optronics Trailer Wiring

  • How To Hook Up Trailer with Two Brown Wires to Vehicle with One Brown Wire
    There should be five wires on your trailer side connector, a white wire which is for a ground, the yellow/brown and green/brown are for the running lights, a green wire for the right turn/stop light, and a yellow wire for the left turn/stop light because you have a wishbone wiring harness like part # A35W42B. In order to attach these wires to the vehicle side connector you will need to attach both yellow/brown and green/brown wires to the brown wire, the yellow wires together, and the green...
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  • How to Ground Lights When Re-Wiring Aluminum Frame Snowmobile Trailer
    Although it may not be absolutely necessary, aluminum does not conduct well so running the ground wire to your aluminum frame is not recommended. Instead, you can use # DW02359-1 to run individual ground wires for each light up to your main ground wire at the tongue of your trailer. This will keep everything working properly and prevent the wide range of issues a bad ground can cause.
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  • Can a 4-Way Be Wired to a Trailer with 3 White Wires
    Based on the colors of the wires you have you could pretty easily wire a 4-way to your trailer. The part # A35W42B would work well. You would just need to match the colors of the connector to the wiring of your trailer. All of the whites would need to run to the single white wire of the 4-way but the rest of the wires would match right up. The white is ground. The brown is running light. The green is right turn/stop. The yellow is left turn/stop.
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  • How to Wire Electric Brakes on a Tandem Axle Trailer
    If your trailer has 7 wires running all the way back to the brakes, then yes, you can tap into the existing wiring. Each of your new brakes will have two wires for the brake magnet. One wire is for 12 volt power to the brake magnets and the other wire should be grounded either to the trailer frame or to the main trailer ground wire. It does not matter which wire is used for power or ground because they are not polarized. If the trailer wiring is running down the left side of the trailer,...
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  • Troubleshooting No Running Lights on Trailer but Turn Signals and Brake Lights Work
    The 4-way on your trailer is what's known as a wishbone connector like part # A35W42B. Two of the wires are the running light circuit which is a little easier to install since you can run one down each side of the trailer. This way you don't need a jumper wire to go from one side to the other. A wishbone 4-way is compatible with a standard 4-way, so your problem is somewhere in the wiring itself. I would start by checking the 4-way on the truck with a circuit tester, like part # PTW2993....
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  • Heavy Gauge Trailer 4-Way Wiring, 16 Gauge
    The longest 4-way harness we offer that has all 16 gauge wire is the Wesbar Harness part # W787274 which is 14 feet long. For one that is 30 feet long that has a 16 gauge ground wire and 18 gauge signal wires you would want the part # W002230.
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  • 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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  • Which Wires Are Used When Installing Marker Lights On Trailer
    For a typical trailer wiring you will have a brown and green wire for the right-hand side of the trailer and brown and yellow wire for the left side. If this is a new wiring installation and you are installing wiring like part # A35W42B, the brown wire that runs down each side of the trailer is for the marker lights and taillights. The yellow and green wires are for the left and right turn signals. You will want to tap into the brown wire for the marker lights. If you are adding marker...
    view full answer...
  • Wiring Trailer Brakes On a 5TH Wheel Trailer
    For the wires coming from the brakes they do not matter as they connect to the magnets in the drum brakes which are not polarity specific. So one wire from each brake will connect to the frame/ground wire as a ground and the 2nd wire will connect to the positive wires coming from the 7-way. The brown wires running through the axle are simply put there by the axle manufacturer so you do not have to run wiring down both sides of the frame. As for the 2 white wires on your 5th wheel you...
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  • What is the Wire Gauge on 10 Inch Electric Trailer Brake Magnets
    The magnet wires on Electric Trailer Brake Assembly # A35W42B are 18 gauge. The wiring going to the brakes from a trailer connector is usually larger such as 10 gauge # 10-2-1.
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  • Installing the 4-Wire Pigtail of the Optrionics Tail Light # STL68RB to 5 Wires from Vehicle
    You may want to double check your 5 way from your vehicle, because normally the stop and turn signal functions are combined on a single wire and are separate wires based on left side and right side for turn signal. So, you'd have ground, left turn and stop, right turn and stop, running lights, and reverse as your 5 wire functions. I recommend using a circuit tester like # PTW2993 to test each pole function on your vehicle. The LED Trailer Tail Light - Stop, Tail, Turn, Backup - Submersible...
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  • Recommended 5-Way Adapter for Vehicle 4-Way Trailer Connector Wiring Harness to Work With Trailer
    For your trailer with 5-way flat connector to connect to your vehicle 4-way flat, I recommend the Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End # C57187 or the Tow Ready # 20036. The blue wire will connect to your reverse light wire at your tail light utilizing the quick connect supplied with this adapter.
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  • Troubleshooting Trailer Lighting That Stops Working with Headlights On
    Your main problem is an insufficient ground for the trailer wiring. Try improving the connection of the main ground wire of the trailer wiring harness. Make sure it is attached to a clean metal surface. Or you can run all of the trailer wires back to the main ground. This is actually the ideal solution. But you can also check the current grounds for the lights to make sure they are making a solid connection to a clean metal surface. What you described is the classic insufficient ground...
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  • Recommended Wiring Harness With 4-Way to Rewire Flatbed Trailer
    The 35 Ft 4-Way Trailer Wiring Harness # A35W42B you were looking at is what I recommend. This will give you plenty of extra wire to run to your side marker lights. I always like to have extra just in case since running out of wire in the middle of a job is the worst. Any extra you don't need can be cut off when you wrap things up. This also runs a little cheaper right now than a 25' harness like # A25W2GWB so it makes sense to get the longer one.
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  • Rear Brakes On Trailer Grab More Than Front Brakes
    If the trailer is wired correctly then the front two and rear two breaks should receive about the same amount of voltage. If you test the brake output wires just before the magnets that will allow you to confirm this. If they have different voltage then you have any issue with your wiring. If the front and rear braking assemblies are both receiving the same amount of voltage then most likely the braking assemblies are not adjusted properly. If you have manual adjust assemblies then there...
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  • Adding Separate Turn Signals to a Trailer Towed by a Honda Goldwing with a 5-Wire Harness
    Based on the wiring functions you have given for the 5 wires on the bike it looks like it is already converter down to a 2-wire system. What you will need on the trailer side is a converter to separate out the turn and brake signals since they are presently combined. You will need # 118158. The green wire will attach to the green on the converter, yellow goes to yellow. Brown will bypass the converter. Then on the output side of the converter the red wire will need to be split by attaching...
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  • Solution for Needing Replacement 4-Way that Has 6-Wires Ran to It
    The type of trailer wiring connector you have on your trailer is a wishbone 4-way that has the running light and ground circuit split into two wires. What you can use for a replacement is the Optronics part # A35W42B which has the running light circuit (brown wire) split off in to two circuits. The ground wire is a single wire but you would need to run both of your trailer's ground wires to it and you'd be set.
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  • What Does Brown and White Wire of Trailer Wiring Run To
    The brown wire of trailer wiring is the running light/marker light circuit and the white is ground. So on your setup that has a brown wire that would be where you'd run the marker light circuit to and then the white would get the ground circuit. You can run this to the frame of the trailer if you want or back to the main ground circuit of the trailer wiring.
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  • How Do The Breakaway Switch And Electric Brakes Connect To A Trailer's 7 Way
    There will be two ways of getting your brakes and break away kit connected to the 7 Way plug on your trailer. First will be to simply splice the wires together, but this can be a bit of a pain as you can end up having several wires connected together. The second way, and the much easier way as well, is to use a junction box, like the Buyers Products # 3375601101. This will require you to mount the box and use ring terminals, like the # 44-5310A, to connect everything, but it is the way...
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  • How To Convert A Wishbone Trailer Wiring Harness To A Regular 4-Flat Trailer Wiring Harness
    It sounds like you have a wishbone wiring harness install on your trailer. A regular 4-way wiring harness has 4 wires from the back of the connector, 1 for left turn/brake typically (yellow), 1 for the right turn/brake typically (green), 1 for the tail lights typically (brown), and 1 for the ground typically (white). A wishbone 4-way connector has 5 wires, 1 for left turn/brake typically (yellow), 1 for the right turn/brake typically (green), 2 for the tail lights typically (brown w/ yellow...
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  • Installing a New Trailer Connector that has 2 Brown Wires on a Trailer
    It sounds to me like you have a wishbone wiring harness on your trailer similar to part # A35W42B. Your trailer may not have a 4-way but the concept is the same. The brown wire is traditionally the running light circuit and a wishbone harness has two of them so that one can be run down one side of the trailer and the other down the other side. It keeps you from having to jump the running light circuit across the trailer somewhere. If I'm misunderstanding something and this doesn't help...
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  • Replacing 5-Wire, 4-Way Wishbone Trailer Connector w/4-Wire Connector Causes Lights to Fail
    On your trailer you originally had what is called a wishbone harness. This type of harness has the running light circuit split at the connector so one wire will run to the left side, the other to the right side. This is so you do not have to have a jumper wire between the 2 lights. What you could do is connect just one of the brown tail light wires, tape up the other, and have a jumper go from one side to the other. The other thing you can do is use a new 4-Way wishbone wiring harness...
    view full answer...
  • What Wire Gauge is Used on the 35 ft. Wishbone 4-Way Trailer Wiring Harness, # A35W42B
    I went out to the warehouse and pulled a 35 ft. Wishbone 4-Way Trailer Wiring Harness, # A35W42B, and used a wire gauge tool to measure the wires. The copper wire itself is 20 gauge. If you measure the wire with the insulation on it then it is thicker but wire gauge corresponds to the strands not the insulation part.
    view full answer...
  • How to Wire Trailer with 5 Wires to Connect with Truck with 4-Way Flat Connector
    Your trailer has what is referred to as a wishbone wiring harness which uses a separate running lights wire for each side of the trailer, such as with the Optronics # A35W42B. The green/brown wire is likely for the right side running lights and the yellow/brown wire is likely for the left side running lights circuit on your trailer. Both of these wires will need to be connected to the running lights circuit on the trailer's 4-Way connector. This will allow it to connect with the standard...
    view full answer...


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