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

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

Item # A35W42B

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Optronics Trailer Connectors - A35W42B
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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. Lowest Prices for the best 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 800-298-8924 for expert service.
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Optronics Wiring - A35W42B

  • Trailer Connectors
  • Trailer End Connector
  • 4 Flat
  • Plug and Lead
  • Optronics
  • 35 Feet Long

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


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

Alternate part number: A-35W42B






California residents: click here


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


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




Video Transcript for Trailer Wiring Harness Installation

Today on our trailer, we'll be doing a rewire using the 35' Wishbone 4-way trailer wiring harness with 42" ground wire, from Optronics, part number A35W42B. Now we went ahead and already removed all the old wiring on this trailer before we began this video. So now we're ready to start with a clean slate. To begin with, we're going to go ahead and tape the two ends of the wiring together to make it easier to feed back to the back end of our trailer. We're going to go ahead and work our way through and tape up about every 5' to 6', just to help keep the wiring together, so when we pull it through the holes already in the trailer, it'll make things a little easier. Now we're going to begin up here at the tongue.

We went ahead and we're going to add about a 4' or 5' section or wire loom, part number 459075-1. We're going to use about 6' total. Now that we're got the loom over the end of the wiring, we're going to go ahead and use some electrical tape to help tape it up. On this particular trailer, we're not going to use the wishbone style, as we're going to run both wires down the same side of the driver's side of the trailer, and then take the passenger side and run it across the back, as this was how the trailer was already wired previously, so there's already holes in the trailer for us to route the wiring. Now we also need to find a suitable ground location, where we use a self-tapping screw and the ring terminal already on the wire.

As you can see here, we found a good cross member on the trailer that we'll be able to put a self-tapping screw in to make a good ground. We're also going to be using some 1/2" loom clamps, which are part number A0500. Now we'll go ahead and finish pulling the wires to the back of the trailer. As you will notice, wherever we went through the trailer, we went ahead and used a little electrical tape where the wires went through the trailer to give it a little extra protection, so when the wires move up and down they don't wear through. We also went ahead and put a zip tie on each to help keep the wires from moving too much.

Now that we've got the wires routed to the back of the trailer, we're going to go ahead and pull the green and the brown wire over to the passenger side of the trailer. Now this wiring harness is much longer than we actually need for this trailer, but we're going to go ahead and route the wire around through the center of the cross member in the back, in case if we ever have to change the lights we've already got some longer wiring there. We'll cut the wire to length on the driver's side, split apart the two wires, and strip back the end. Now the lights on this trailer have three wires coming out of them, a red, a black, and a white. The black wire will be connected to the brown wire, which is the running light wire.

The red wire will connect to the yellow or the green, depending on which side of the trailer you're on. And the white wire we'll put to a ground. We'll go ahead and connect the yellow and the brown wire with the red and the black wire on the driver's side. To do this, we'll use some bud connectors, part number 05730-5, and some electrical tape. You'll also notice that we used about 6" of wire loom here, just to give a little extra protection for the wires coming out of the bottom of the lights. Once we connect the bud connectors on the driver's side, we're going to go ahead and slip a loom clamp over the bud connectors and wiring. When we put our self-tapping screw in, we'll go ahead and slip the ring terminal from the white wire, which is the ground wire for this light, over the screws so that we can make our ground here. Now we're ready to go over to the passenger side, and we'll repeat the same process. But on this side we use the green wire to the red and the brown wire to the black, and again the white wire will go to the ground. We use the same thing where we use two bud connectors, a loom clamp, as well as the self-tapping where we use that for the ground. Now that we have all our connections made and the wire zip tied up, as well as clipping off any excess zip ties, now we're ready to go ahead and test our light functions. To do this, we will use a tester. We'll test to make sure that the running lights work, the right turn, the left turn, as well as the brake lights. As you can see here, all the light functions are working properly. And with that, that will conclude our installation of the 35' Wishbone 4-way trailer wiring harness with 42" ground, from Optronics, part number A35W42B.


Customer Reviews

35 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 42" Ground - A35W42B

Average Customer Rating:  4.9 out of 5 stars   (403 Customer 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.

- A35W42B
by:

What was needed to rewire boat trailer. 640879



- A35W42B
by:

Harness was exactly what I needed and wanted. Most try to use a 4 wire system (which will do) and then split the running lite wire. 8 times out of 10 they can't get it right and end up taking it somewhere for fitting. etrailer.com had the exact item. Life is good again. quick shipping too. 615822



- A35W42B
by:

I recently bought a 2004 Trailstar boat trailer for a boat with a seized engine that a friend is giving me. The trailer was a great deal, but they told me the lights worked and they didn't. The connections were all corroded, none of the side lights were hooked up, and there wasn't enough slack in the existing harness to connect anything to it. Your harness was plenty long and only $15! I just wish that the ground wire was as long as the other wires. The ground wire only reached to the front part of the trailer and there's a hinge with rubber bushings halfway along the tongue. I had to ground the front part of the tongue to the part after the hinge. And then I used the ground wire in the old harness to ground the taillights. 619248



- A35W42B
by:

Website was very helpful as to finding the correct part numbers. My order processed and was shipped in great time! This is my first time dealing with this company, but not my last. I’m recommending to all of my family and friends! 609437



- A35W42B
by:

I want to thank you for all your help with my trailer you were more helpful than you realize. So this is my trailer for a 22' Flats Cat shallow draft Catamaran. I totally dismantled my trailer and buffed by hand with a wire buffer and sand blasted in some spots and applied multiple coats of some very expensive galvanize paint (Z.R.C.). I installed all new C. E. Smith Carpet (about 80'), seven new LED waterproof lights, new springs, new equalizers, new tongue jack, new wench, new safety chain, new chain brackets, all new SS hardware and a 35' long wiring harness. I was able to send only one review with a picture of the safety chain and brackets. I'm having a little trouble with the rest..oh some of these items were bought locally or from your competitors, until I found ETRAILER. Your prices were cheaper for the exact same things. Your helpful how to videos were helpful. And Rose, your personal helpful knowledge made my buying experience very pleasant, I actually enjoyed talking to you! Thanks to ETRAILER and specifically to Rose G. 497941



- A35W42B
by:

Excellent product and shipping! Let me say all I could find everywhere was 25 ft. The extra 10 feet I get with this item NOW allows me to fix the short in my utility trailer. Thank you so much. 146168



- A35W42B
by:

The plug looks and feels solid! This is the only place that had a long enough wiring harness to do what I needed. Shipping was also very fast! 471215


Comments

After one year, It is still working great! It makes all the difference having long enough wires to where there is no splicing on a saltwater boat trailer.

Eric - 01/29/2019

49013

- A35W42B
by:

I am very satisfied with my experience with etrailer. The parts I received appear to be very good quality. I have not installed them yet though as I am waiting on Hurricane Michael to pass through. However the lights do seem to be very solidly built. I needed this style and etrailer was the one that had it. 572964



- A35W42B
by:

Fix perfectly and all lights work great. Thanks Etrailer 568434



- A35W42B
by:

Customer Service This is my second purchase with etrailer.com. My first was a factory wiring harness for my Ford Escape. Perfect fit and the included directions were right on. I now need to replace the plug on my trailer and it is a 4 prong but has 5 wires which none of the local stores had. Back to etrailer.com where I identified a matching kit with ease. They responded to my orders the same day I placed them and shipped next day with plenty of correspondence during the purchases. The products and service are top knotch. I highly recommend them, you won't be diappointed. Sincerely, Glen Lang 4218



- A35W42B
by:

Great product. Nice to have two running light wires (brown pin 2)so I could feed running lights and license light without splicing wires... 158701


Comments

Perfectly

Tom F - 10/31/2015

15741

- A35W42B
by:

this product was absolutely prfect. I was very satisfied very short time for delivery.I do and always will shop for all my trailer needs at etrailer .com. They are the best 572165



- A35W42B
by:

This is a great quality product. Moreover, I initially purchased a similar product from Walmart which was 20 feet long, but then I checked with etrailer and was able to obtain an identical product that was 35 feet long for only a couple bucks more - a much better deal. This gives me more latitude to run the wire without worring that it might end up being too short. I'm rewiring a flat bed trailer and plan to run the wire inside of 1/2 inch pvc so it will be protected and I'll never have to do it again. 185237



- A35W42B
by:

Worth it's weight in gold when it came to wiring my trailer. I bought this for a homebuilt camper project and this made wiring my lighting simple. Although, my only complaint would be the short 42" ground wire. I'm a firm believer in not using the trailer frame for grounding - I consider it a sloppy installation practice. I'd rather run the extra wires and have dedicated ground wires run to all lighting 359697



- A35W42B
by:

Perfect! Just what I needed!! I could only find a harness plug with one brown wire (4 wires total) at my local stores. I "googled" the problem I had (my harness plug had 2 brown wires). A rep from etrailer had answered someone's same question on a message board. It was a detailed explanation as to why one would need this part. Then the rep put a link to the etrailer site. And there is was, the harness plug with 2 brown wires (5 wires total) and at an agreeable price to boot!!!!! And now I know about the etrailer website!!!! 210017



- A35W42B
by:

Perfect description, Amazingly fast delivery, Wonderful communication. Will for sure be shopping here again. 225773


Comments

Awesome product worked great will reccomend to my friends to buy products from here.

Willie - 09/15/2016

21020

- A35W42B
by:

Excellent product!!! I bought 2, one for each of my trailers, a year ago. Still working great! Extremely satisfied with the quality of this product! 730890



- A35W42B
by:

Good quality and fast service 725279



- A35W42B
by:

Everything is still in perfect working order after the one year mark in saltwater usage. 725200



- A35W42B
by:

simple wiring harness 721707



- A35W42B
by:

Previously bought a trailer light kit from a different vendor and the wiring harness in the kit was too short. This wire harness worked out great with some length to spare for future repairs. Quality product. 721402



- A35W42B
by:

Fast shipping, Had product I needed and it works great. will order another for my other trailer. 720496



- A35W42B
by:

Product was as described. Looking for something bright and it has preformed perfectly. 719637



- A35W42B
by:

I just received this today. 2 days shipping to Illinois from wherever etrailer.com is. Pretty fast. Looks to be exactly what I ordered. I will install this sometime this week. 718937



- A35W42B
by:

A good quality product. Awesome pricing and fast shipping. I would reccomend etrailer to anyone wanting quality boat and trailer parts.. 718886



- A35W42B
by:

Product arrived on time they even upgraded my delivery, really appreciate it ,I will continue business with you guys 717700



- A35W42B
by:

Easy to install and works well 717310



- A35W42B
by:

Easy and fast 716128



- A35W42B
by:

Great product, easy to swap out the old wiring harness for this one. Have used almost a year and have had zero issues. Would recommend! 715746



- A35W42B
by:

Good quality products, and very fast shipping. I have trusted e-trailer with past purchases as well. This order included led tail lights and wire harness for my pontoon trailer. I needed a 35 foot harness and e-trailer had it. They are very difficult to find. And the lights and wiring was first class. Also e-trailer provides good videos for product instructions. Great company. 715040



- A35W42B
by:

Received as expected and on time. Quality appears very good and is exactly the type which will fit my Ford "slotted" holder. Will install tomorrow. Good doing business with these folks. 714964



- A35W42B
by:

Quality Harness with solid plug. Great Shipping Time, Very Reasonable. Highly recommended K. SAUNDERS CHARLESTON, S.C. 714959



- A35W42B
by:

Received my new lights and harness on time and nicely packaged. There was a mix-up with the harness and Stacey took care of it immediately. Thanks for great customer service! 711516



- A35W42B
by:

Parts boxed up good. Arrived on time an in good condition.thx to UPS & etrailers shipping dept 710997



- A35W42B
by:

Allows for ample room when rewiring a trailer. Easy to install. I couldn't easily figure out the gauge and i am still needing that info to make sure i have the right connections hooked up. 707286



- A35W42B
by:

For 10 foot utility trailer ......a lot of extra wire 699515



- A35W42B
by:

Great price, fast delivery, great instructional video! Awesome!!! 698118



- A35W42B
by:

great product, excellent service 697086



- A35W42B
by:

I received it be the time the website promised even though I had to phone the order in. 690806



- A35W42B
by:

Parts received in a timely manner as ordered. Parts continue to perform well. Thanks for getting us up and running again! 689890



- A35W42B
by:

I purchased this product to re do my boat trailer wiring. After owning it a year, it has done great. Saltwater and freshwater. No problems. Highly recommend. 688505



- A35W42B
by:

Product is exactly as described, delivery was prompt. 682629



- A35W42B
by:

Exactly as described. Fit well. Nicely suited for the application. Properly priced. I will gladly consider you for future component needs. 681712



- A35W42B
by:

Perfect product for re-wiring a trailer. 681176



- A35W42B
by:

I looked for a week at local stores. No one had the lighting wiring I needed for a basic Tractor Supply 5x8 carry on trailer. Including Tractor Supply where I bought it a year ago. etrailer had it and while I wasn't happy paying $17 extra for 3 day shipping. They got it to me in those three days. They shipped immediately and made the deadline and didn't drag it out through the weekend. $17 bucks, whatever I no longer have to drive around searching and I can fix my trailer before the weekend when I have a great need for it. Well deserved 5 stars. 679519



- A35W42B
by:

The duplex tail light wire (brown) is a great feature. 679416



- A35W42B
by:

The product arrived fast, the online description matched perfectly to the parts received, I recommend it 678987



- A35W42B
by:

Worked very well and was just what I ex pected!! 675195



- A35W42B
by:

Did exactly like I wanted. Fast deliver y. 672912



- A35W42B
by:

great company 672871


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Ask the Experts about this Optronics Wiring

Do you have a question about this Wiring?


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  • 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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  • Troubleshooting Right Turn Signal Not Working On Trailer With Wishbone Harness
  • It looks like you have a traditional 4-way connector on your Toyota RAV4 and wishbone style connector like part # A35W42B on your trailer that allows you to run separate tail lights back to each side of your trailer. You can replace the wish bone trailer connector on your trailer with A35W42B but that may not solve your wiring issues without knowing for sure where the problem is. First you want to make sure all of your ground connections on the RAV4 and the trailer connector are attached...
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  • Help Wiring New Trailer with 5 Wires Coming From Each Tail Light Assembly
  • Since you have 5 wires coming from each tail light on your new trailer, the first thing I recommend doing is testing each wire for function. You can use a spare 12V battery to test each wire to see what they active on the tail light assemblies. Simply connect the battery's negative terminal to ground, then one by one, apply the positive terminal to each of the circuits. Since it appears that your tail lights do have an amber light, I would expect 4 wires to be coming from each assembly...
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  • Availability of an LED Trailer Tail Light Kit that Will Fit a Snowmobile Trailer
  • In terms of a pre-assembled kit with everything included, the closest we have to something with tail lights that are 2-1/2 inches tall would be the Trailer Light Kit with 25 Foot Wiring Harness, # TLL16RK. The included tail lights in this kit are 2-7/8 inches tall. Another option would be to get a couple of # STL76RB lights, and a 4-Way, trailer side wishbone wiring harness, # A35W42B. I have included a link to a video showing the installation of this wiring harness for reference.
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  • Replacing 4-Way Wishbone Connector on Trailer with 7-Way
  • It sounds like what you have now on your trailer is a 4-Way wishbone harness that uses a running light wire on each side of the trailer. This is why there are 5 wires going to the connector instead of 4. A wishbone harness makes it a bit easier to wire a trailer since it eliminates the need to run a jumper wire between the two sides. I am not sure how you are currently connecting the wires from the broken 4-Way to your new 7-Way plug but both of the running light wires on the trailer...
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  • Trailer Wiring has 3 Wires for Brakes But Magnets Only have 2 Wires
  • Electric trailer brake magnets only have a power wire and a ground wire (doesn't matter which is which). The power wires will attach to whichever of the 3 wires carries the brake signal from the brake controller. One of the other wires must be a ground but you can ground the magnets to any clean metal surface. The third wire could be for something else or it could be a power or ground that tees off from the main ground/power wire.
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  • Converting a 5-Way Trailer Connector on a Honda Goldwing to a Standard 4-Way Flat
  • Since motorcycles have separate turn signals and brake lights they will only work with a trailer that either also has a separate system or would require a converter to make the trailer and bike compatible. Right now, the separate brake light circuit has no where to go on the trailer. It would be easiest to convert the connector on the bike using converter # 119178. On this converter, the red input wire is for brake lights only from the bike, green is right turn signal only from the...
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Info for this part was:

Expert Research:
Mike L
Expert Research:
Robert G
Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
John H
Expert Research:
Adam R
Expert Research:
Rachael H
Expert Research:
Jeffrey L
Expert Research:
Victoria B
Video Edited:
Zack K
Updated by:
Brian T

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