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...
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• 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...
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• 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.
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• 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...
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