Lowest Prices for the best wiring from Optronics. 35 ft. Wishbone 4-Way Trailer Wiring Harness with 42" Ground Wire part number A35W42B can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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Price: $11.72

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

Item # A35W42B

Retail:$14.95

Our Price: $11.72

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



Optronics Wiring - A35W42B


35' Wishbone 4-Way Trailer Wiring Harness with 42" Ground Wire

This is a 35' split wishbone 4-way trailer wiring harness with four conductors and a 42" ground wire.

  • 4-pole trailer end connector built-in
  • 35' long harness
    • 42" long ground wire
  • Each wire is 20 gauge
  • Y harness contains an extra tail light wire
    • Makes wiring a trailer quick and easy

Because the brake signal is sent along the same wire as each turn signal, the tail light signal is the only one that needs to be run along both sides of a trailer. The y-harness with 4-pole connector contains 2 separate tail light wires (brown wires), one bundled with the left turn and brake wire (yellow wire) and one bundled with the right turn and brake wire (green wire). It's the most efficient way to wire your trailer.

Manufacturer Cross Reference
Harness will work as an exact replacement for:
Truck Lite # 108835






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Value - This item

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


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

229 reviews

Code: A35W42B


Retail:$14.95

Our Price: $11.72


  • Wiring
  • Trailer Connectors
  • Trailer End Connector
  • 35 Feet Long
  • Plug and Lead
  • 4 Flat
  • Optronics
Economy
Price: $9.06
$2.66 Less

20 ft. Wishbone 4-Way Trailer Wiring Harness with 30" Ground Wire


20 ft. Wishbone 4-Way Trailer Wiring Harness with 30" Ground Wire
Optronics Wiring

113 reviews

Code: A20WB


Retail:$9.95

Our Price: $9.06


  • 20 Feet Long


20' Split wishbone 4-way trailer wiring harness with 30" ground wire.

more information →
Premium
Price: $20.43
$8.71 More

Wesbar 5-Pole Flat Connector - Wishbone Style - Trailer End - 40' Long


Wesbar 5-Pole Flat Connector - Wishbone Style - Trailer End - 40' Long
Wesbar Wiring

22 reviews

Code: W002290


Retail:$22.95

Our Price: $20.43


  • 40 Feet Long
  • 5 Flat
  • Wesbar


This wishbone-style, 5-wire flat harness is great for a trailer with a surge coupler. The 40' long harness includes a 4' long ground wire and a blue auxiliary wire that signals your trailer brakes to disengage while you are in reverse.

more information →


Video of 35 ft. Wishbone 4-Way Trailer Wiring Harness with 42" Ground Wire


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

Average Customer Rating:  4.8 out of 5 stars   (229 Customer Reviews)



- A35W42B

by: Fred C. S.07/08/2014


Great delivery and cost was low. Exceeded my expectations. Easy installation. Note: I have a patch work steel frame and have trouble getting a good ground. Wooden trailer bed with segmented (and rusted) steel frame. So I soldered a long wire to the white ground wire, and ran the entire bundle to the rear. I ran a ground from each light directly to my new ground wire. Works great for my special application. I love Etrailer. 140049

Comments

Everything is fine and I want to thank you for your fine service. The trailer is working very hard for the family.

Fred C - 07/09/2015
13222


- A35W42B

by: Joel T.03/23/2014


This item would be perfect if the ground wire ran to each tail light with the rest of the wiring and it came with a schematic, but for less than $20, I'm still extremely impressed. No more phantom intermittent trailer light issues. 121850

Comments

Absolutely no issues still very happy.

Joel T - 03/23/2015
10243


- A35W42B

by: Tanner J07/07/2015


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: Willie09/16/2015


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: cj08/19/2015


Worked great, I had a hard time finding wire in the length that I needed. Was easy to install. 220248

Comments

The length was correct. Did not have to splice any where. I would purchase again if the time comes.

Carl J - 08/18/2016
20350


- A35W42B

by: Mike M08/06/2013


This was long enough to do the job of adding a light connection on the rear of a 29 foot travel trailer to pull my smoker behind it. 93661

Comments

This is still working great!

Mike M - 02/04/2015
9267


- A35W42B

by: Tom F.10/31/2014


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: JP09/05/2015


Top quality, perfect length, simple wire harness. 224248

Comments

All the products are fabulous!! Thanks for following up with me. They are in use regularly.

JP - 09/13/2016
20946


- A35W42B

by: Adam M.08/13/2013


Product worked perfectly and the two separate brown wires made the job even easier. The install took less than an hour. 94787

Comments

Still works perfect.

Adam M - 02/12/2015
9465


- A35W42B

by: Jim W.06/13/2011


The product is fine and will do the job as required. As a novice, I was disappointed not to have some sort of diagram included with the item. A quick Google search gave me what I needed, but I think it should have been included, maybe with some helpful installation tips. The length was greater than I needed, but I coiled the wire in a couple of areas in case I need to make new light connections in the future. This way the wire is there and I won't have to splice in new wires. I'll have to see how the quality holds up over the next couple of years of salt water launches. Price was much better than Lowe's. 16844



- A35W42B

by: Mike W.05/27/2011


I had purchased a replacement harness for my 21 foot boat trailer before looking closely at how the manufacturer had rigged the wiring for the lights. Unfortunately, the running light circuit was run down the left side and wrapped around the rear to the right side making that run over 30 feet and making that harness unusable. The right side did not have retainers (welded to the frame as did the left) to run a true wishbone harness on both sides from the front. This 35 foot harness (though a wishbone) works perfectly to re-rig the lighting as it was originally. No adapting or modifying necessary. 15564



- A35W42B

by: Glen L.12/16/2010


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: Danny05/12/2017


I received my wiring harness and other components on the day in which they were promised for delivery. I had already viewed one of your posted videos on how to re-wire a utility trailer so I promptly installed the wiring harness and connected it to the lights which I had already mounted. Everything worked great! This was the first time I had re-wired a trailer and was initially apprehensive about doing the job myself. Your video made the difference! I have marked your website URL for future reference. You will be my "go to" site for trailer accessories and information. 380525



- A35W42B

by: Gino, Jr.08/19/2014


Excellent product no hassle installing! 147313

Comments

Its fantastic no problems and doing well.

Gino, J - 08/19/2015
14408


- A35W42B

by: Randy S06/20/2014


Great fit for my boat trailer!! 136721

Comments

Excellent lights still working fine after a yr!

Randy S - 06/20/2015
12659


- A35W42B

by: DougP09/20/2012


Nice wiring kit for a 6-12 foot utility trailer. The only thing missing was the instructions, which were on the website / U-Tube as a video with a written transcript. The only thing that would have made it better would be to include accessories like clips, tap splice connectors or wire nuts. Eventually, also purchased a channel light kit, and running lights. the light kit came with the accessories mentioned and a 25' version, but the wires in that set were not as nice as these. This was a good purchase for my application. 55338



- A35W42B

by: Larry S04/14/2015


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: Scott S.03/28/2017


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: Glen S.08/12/2014


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: Dan10/28/2013


I looked around for this product locally and on the web got quite some time before finding it here on etrailer. This connector comes in so many configurations it's easy to buy the wrong one. The description was enough to give me confidence. Package came swiftly, even though shipping cost as much as the item, but that's not etrailer's fault. Will shop here again. 105406



- A35W42B

by: Jim Mc12/15/2010


Trailer harness kit Katie, 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. 4173



- A35W42B

by: Eric C.05/10/2013


This harness made for a seamless installation. I simply tied some string to the ends of my old wiring, pulled it out, and pulled this one back in. Then crimped some connectors on the end and plugged in my lights. My whole trailer re-wire took about 1 hour. This product has the wires bonded together (Grn/Brn & Yel/Brn) for quick and easy installation! 79738



- A35W42B

by: Jim W07/09/2014


This was exactly what I needed to re-wire my boat trailer. I had not been able to find the length I needed locally so I began shopping on line for this. I had never used this web site before but I found this product it was exactly as advertised. It arrived with in 4 days of ordering. Simple and easy. I will use this web site for future orders. 140208



- A35W42B

by: JIM P.08/08/2013


I BOUGHT A USED TRAILER AND THE LIGHTS DIDN'T WORK. I FOUND OUT THAT MICE HAD CHEWED THE WIRING THAT RUNS THROUGH THE TUNG. THIS PRODUCT WAS A GOOD REPAIR SOLUTOIN. IT ONLY HAS A 42" GROUND WIRE. SO I HAD TO ADD SOME GROUND WIRE BECAUSE MY TRAILER RUNS THE GROUND WIRE ALL THE WAY TO THE LIGHTS INSTEAD OF RELIAING ON TRAILER FRAIM GROUND. 93919



- A35W42B

by: Chris P08/24/2015


Excellent harness, cut the old plug and taped the old wires with the new to pull it thru the conduits. It had the common wire for both sides. Easy installation and cheap. On a 14' trailer I bet I only had 5' left. Between the tongue and a 3' extension for vehicle, then up and out back and I did a loop underneath for a liitle extra. 221421



- A35W42B

by: momule10/30/2015


Rewired my boat trailer (14' jonboat) This wishbone wire set is all you need and the price is great. I bought 35' kit because it's better to have too much than not enough. Price is great and the kit has a running light wire for each side. Ground goes from truck through 4 wire flat plug to trailer frame via 4' white wire. 231164



- A35W42B

by: Dan S04/28/2017


Perfect length for my 25' pontoon trailer. It has sidelights and I wanted to be sure to get a little extra length to accommodate that. The 4 flat connector is sturdy plastic not flimsy rubber like cheaper brands. Shipping was fast and the price for this was less than the price of a 25' harness from other online sellers 373824



- A35W42B

by: Donny mcknight12/22/2016


Thanks George I'm always Leary ordering stuff online 1 you really don't know when your getting it 2 until you actually have it in your hand you don't know the quality of it and 3 you've already paid for it . I'm very happy with promt service quality and price I will use you again thank you and God bless. 327412



- A35W42B

by: Tim A.07/01/2016


After hours of Googling for a source for a replacement plug with the correct "wishbone" configuration, I finally found your website. Your folks are great! Very fast shipping, very clear and accurate documentation on your website to explain this item and how it differs from a standard 4 wire plug. 267197



- A35W42B

by: Patricia Taylor10/24/2015


The product was exact as ordered. Arrived in a very timely manner. It was easy to install and It was a pleasure to deal with this company. The questions I had were answered quickly and they had the parts I needed. I appreciate great customer service and speedy delivery. Thank you, 230703



- A35W42B

by: Teri Stohlberg10/15/2014


I bought the wiring harness for my husband to rewire our snowmobile trailer. He claims he doesn't know much about electrical stuff, but he was able to figure it out pretty quickly and it worked great! The product arrived quickly and I would definitely buy another product from etrailer. 155868



- A35W42B

by: BobTheBanker12/11/2014


Exactly what I ordered. Very reasonably priced. I looked for this at two trailer companies locally AND on Ebay - NO ONE had these 4 Flat wires over 25' long - NO ONE! The local guy said I would have to make it myself! Shipped Quickly. Perfect Transaction. Will use again! Thanks! 164253



- A35W42B

by: Rich P.10/19/2012


4 pole 35 foot trailer wire harness. This is a great product. 35 feet is hard to find at marina's. The 25 foot is quite common but is too short for my trailer. Even on line this is the only 35 foot that I found and it did not cost any more than the 25 foot at other web sites. 57688



- A35W42B

by: Harold B04/29/2017


Really an amazing outfit. The web page provides all the detail needed to make the right choice on parts so its right the first time. The staff are friendly and caring and the delivery was spot on. etrailer is how web shopping ought to be done. They truly set the standard. 374923



- A35W42B

by: Matt11/06/2012


Should have bought it when I got new taillights,wa too much time on old wiring issues.Lifted my trailer up on it's side with my tractor and was done in 1/2 hour.Live and Learn. A couple of quick splice connectors for side lights would make it better than excellent. 58911



- A35W42B

by: dhart2710/06/2014


Haven't installed it yet but it looks like a good quality replacement. Hard to find 35 feet and was glad to acquire it. Service, price, and communication were top notch. I will order more parts from E-Trailer as soon as I am done wiring the trailer. Thanks Dan 154719



- A35W42B

by: jason h.06/20/2014


Thanks etrailer for saving me!!! Mice had wrecked havoc with the pontoon harness and this length was just perfect for rewiring it back to new condition. And as a side note, I was pleasantly surprised how much care was taken to package wire......thanks again 136844



- A35W42B

by: Bob R06/29/2013


I had a hard time finding a harness locally that would fit my trailer which is 28' plus 3 ' to vehicle. the 42' ground wire is a plus. The wiring information that the site provides is a big plus min trouble shooting problems. Will buy again from etrailer 86754



- A35W42B

by: Ron m12/05/2014


Ordered this to replace the that came with the optronics light kit that I ordered previously. The end that came with the kit was not compatable with my vehicle. Going to order another one just like it but shorter for another trailer. Nice quality 163465



- A35W42B

by: Roger G04/06/2017


I have ordered from etrailer.com several times and am 100% completely satisfied. They always have what I'm looking for, prices are very good and delivery is fast. This is always my first stop when looking for trailer parts. Outstanding company! 363869



- A35W42B

by: Rob Roy04/12/2016


Everything came fast. Replaced the wiring harness on the car for the trailer, replaced the wiring harness on my 5x8 trailer, and all the lights on the trailer. All the directions were great and I had no problems with any of the installations. 243978



- A35W42B

by: Alan07/12/2015


Glad I went with the 35' length, routing the wires and having ample pigtail length used almost every inch of the wire for our 24' trailer to wire up a rear hitch for towing our raft. Good quality, great price, fast shipping! Way to go etrailer! 211186



- A35W42B

by: KP09/04/2012


I had a short in the wiring on my boat trailer and instead of trying to track it down I decided to just replace the wiring completely. This was more than enough wire for my 18' SeaRay trailer. The extra long ground pigtail is very convenient. 53911



- A35W42B

by: Glen S.04/08/2013


It looks like just what I wanted, and it will work beautifully, but I have decided to up grade the lights to LED's, because the old 1157s would go out every time I hit a pump in the road, so I have another order to you for those LED lights. 74843



- A35W42B

by: Mike C05/03/2011


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. 12777



- A35W42B

by: Freddy Pichardo04/14/2017


Exelente cableria , tiene muy buena insulacion. La he usado por un año y no he tenido problemas con ella . [Excellent wiring, it has very good insulation. I have used it for a year and I haven't come across any problems with it.] 367314



- A35W42B

by: Steve07/22/2015


This wire harness is just what I needed for my trailer. I was able to install it in about an hour and now all my lights work like they are supposed to. As always, eTrailer provided a good product with fast delivery at a fair price. 213514



- A35W42B

by: Jeff O09/25/2014


I needed to rewire my boat trailer and I could not even find this product in the length I needed at a boat store. I looked and found exactly what I needed on Etrailer.com. I have always been happy with the products that they sel. 153047



- A35W42B

by: Robert M08/19/2016


Quick delivery, excellent product, good quality and easy to install directions. Met all my requirements. Used on my boat trailer and had very excellent results with plenty of length wire for the job. Fine product and supplier. 285583



- A35W42B

by: joe08/09/2012


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. 51192

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Ask the Experts about this Optronics Wiring
Do you have a question about this Wiring?


  • 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,...
    view full answer...

  • Why Does my 4-Way Connector Have 2 Wires Ran to One Prong for the Tail Light Circuit
  • It sounds like you need an Optronics wishbone wiring harness, part # A35W42B. This 4-Way has a prong that has two wires that come out of it. The reason some 4-Ways have two wires coming out of one port is because that prong represents the tail light functions for both sides of the trailer. So one wire would run to the tail lights on one side of the trailer, and the other wire would run to the other. I attached a video below that shows this product being installed onto a trailer and...
    view full answer...

  • 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 tail lights. 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...
    view full answer...

  • Trailer Brake Wiring for Tandem Axle Brake System
  • I'm not sure what the sensor you describe is for. Typically trailer wiring is color coded so that right turn and brake light signal is carried by a green wire, and the brown wire carries the running light circuit. The brake output circuit is usually carried by a blue wire which travels to each brake magnet, where it attaches to one lead from each magnet. The other lead from each magnet will ground to the trailer frame. I'll give you a link to a typical trailer wiring diagram. I...
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  • Wiring an 8x10 Triton Aluminum Snowmobile Trailer with Lights that have Separate Ground Wires
  • Wiring the grounds for your tail lights and the 35 ft. Wishbone 4-Way Trailer Wiring Harness with 42 inch Ground Wire, item # A35W42B, is fairly simple. The 42 inch ground wire provided with the harness is normally attached to the trailer frame near the coupler. Doing this makes the trailer frame a convenient point to ground all of the other ground wires for your taillights and makes it possible to use lights that are grounded through the mounting hardware. This is demonstrated in our...
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  • Wiring Stop Turn and Tail Light Circuits to a Trailer Light
  • Your trailer lights should only have one wire if the light serves only one function (tail light, marker light, stop/turn). The white wire shown in the photo that you attached is a ground wire and will not be connected to the tail light or stop/turn circuits. The bulb attached to your light housing looks like an 1157 bulb, which is a dual filament bulb that has two contacts for two different circuits. You should have two wires on the back of the light housing, one for the stop/turn circuit...
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  • How to Wire a Trailer so that Second Trailer Could Be Towed Behind It
  • The correct part you would need would be the 4-Pole Wiring Harness part # 118603. You would need to use quick splices like part # 804C to connect the wires of this harness to the correct wires of your travel trailer taillight wiring. The brown wires will run to the running light circuit, the green to the right stop/turn, the yellow to left stop/turn and the white to the ground circuit of the trailer. This will give you all of the taillight signals on a 4-way that you would need for...
    view full answer...

  • Wiring Brakes On Tandem Axle Trailer
  • Typically trailer wiring is color coded. The brake circuit is usually a blue wire which travels to each brake magnet, where it is attached to one wire from each brake magnet. The other wire from each brake magnet will ground to the trailer frame. I have attached a drawing that shows how the wiring is typically run for brakes on a trailer. I have also attached a link to trailer wiring diagrams that may help.
    view full answer...

  • 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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  • 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 Does 80 Inch Trailer Mean On Optronics Submersible, Under 80 Inches Trailer Light Kit # TL5RK
  • The 80 inches means the width of the trailer. Trailers that are over 80 inches wide are required to have two side marker lights, one on each side. The Optronics Submersible, Under 80 Inches Trailer Light Kit with 25 Foot Wiring Harness, part # TL5RK, is designed for trailers under 80 inches wide. The 25 foot length of wire that comes in the kit should work fine with your 20 foot long boat trailer. If you are needing a longer 4-way wiring harness I have the Optronics 35 ft. Wishbone...
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  • What are the Functions of a 4-Way Flat Trailer Wiring Connector with 5 Wires
  • What you are describing is called a wishbone harness. This is different than a 5-Way flat connector like # A40W5B that you have referenced. A wishbone harness will have 5 wires, 2 of them going to the running light pin which is right next to the ground pin. This is so you do not have to splice in a jumper wire to go from one tail light to the other for the running light function. A 5-Way flat will have 5 wires (though there are also wishbone 5-Ways) and the extra pin is usually attached...
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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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  • Wiring Electric Trailer Brakes with Magnets that Have 2 White Wires
  • It sounds like the magnets or their wiring could be bad. Your 2012 Chevy Silverado 2500HD is probably sensing the wrong resistance from the trailer brake magnets and that is why you see that warning message. When magnets have 2 of the same color wire it usually means that you can use either one for either function. The black wire with the 12 volt power should not be attached to the brakes. Only the blue wire should connect to the brakes. The other magnet wire should be attached to...
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  • What Circuit Does Trailer License Plate Light Tap Into
  • The license plate light of a trailer will need to tap into the running light circuit of your trailer wiring. The white wire of the light will be the ground and would need to get ran to the frame of the trailer and the black wire will be the power wire for the light and would get ran to the running light circuit. Typically the brown wire of trailer wiring is the running light circuit. This will be the pin closest to the jacketed pin on the 4-way (the ground). I attached a help article...
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  • Wiring Wishbone Trailer Wiring Harness
  • The 5 wire Wishbone Harness with 4-pole connector splits the running light circuit into two wires. One wire would run along the drivers side of the trailer, the other along the passenger side. Typically, the running light circuit is only carried one one wire and at the rear of the trailer, you would need to split off a wire to feed the running light on the opposite side of the trailer. The wishbone harness makes the wiring job a bit neater and eliminates the need to splice in a feed for...
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  • Wiring a 1992 Mazda B2600 With a 4-Way Trailer Wiring Harness
  • Your 1992 Mazda has a 5 wire system and the trailer has a 4 wire system. If you do not have a 4-Way trailer connector on the truck you will need to install one. The 4-Pole Hardwire Kit with Converter, item # 119178KIT will convert the vehicles 5 wire system down to a 4 wire system for trailer lighting. You will need to identify the tail light circuits on the vehicle with a circuit tester, item # 3808 if needed. Once you have the proper circuits identified you will connect the white wire...
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  • Recommended Truck for Pulling 31 Foot 5th Wheel Trailer
  • I would be happy to recommend the type of truck you will want to tow your 5th wheel trailer. For towing a 31 foot decent sized 5th wheel trailer you will want a 3/4 or 1 ton pickup with an 8 foot bed. A 6-1/2 or 6 foot bed would require the use of a slider fifth wheel hitch. An 8 foot bed will require less parts and it will be simpler to operate as a fifth wheel truck. You will be glad you have the 8 foot bed when you come to tight towing situations. Basically the bigger the trailer,...
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  • Trailer Light Kit Recommendation for a Pace Enclosed Trailer
  • For an LED trailer wiring kit that would work well on your Pace trailer I would recommend the part # TLL16RK. This part number comes with everything. The lights are rectangular though. To use the part # ST70RB you would need the grommets part # a70gb, the pigtail part # A45PB, brackets part # BK70BB, and # A35W42B.
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  • Trailer Brake Lights Not Working
  • I am assuming from your e-mail that you used a circuit tester on the plug on your 2002 GMC 2500 HD and all the pins are working. That would lead me to assume that there is a faulty wire somewhere on your trailer. Check the wiring on the underside of the trailer to ensure that all the wire is in tact and correctly run. If only the brake wire is damaged/missing, you can replace it using this wire, item # 10-1-1. If you only need to replace the wiring on the system, you can use this kit,...
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  • Can Master Lock Wireless Backup Camera # 4843DAT Be Used on Back of 23-ft Travel Trailer
  • If your 2010 Toyota Tundra is equipped with a combination 7-way/4-way trailer connector you absolutely can use the Master Lock Wireless Backup Camera System, part # 4843DAT, powered by the unused 4-pole connector. Power is delivered to the camera through the running light circuit on the 4-pole, so all you need to do to activate the camera when you need it is turn on the Tundra lights. As you noted, you will need a 4-pole extension to reach from your Tundra 4-pole trailer connector back...
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  • Options to Replace Square Tail Lights with LED lights for Over 80 Inch and Under 80 Inch Trailers
  • If your trailer came with the square Peterson lights then you can use the Submersible LED Trailer Light Kit, # TLL9RK. The Over 80 designation that you see is a federal guideline for trailers that are over 80 inches wide, and extra lighting is required for these trailers. You should check federal and state lighting guidelines if you are not sure that your trailer has the correct lighting installed on it. At this time we do not have an LED version of the Over 80 inch square tail light...
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  • How to Wire a Trailer for Tail Lights
  • First, lets make sure you have all of the parts you need to wire a trailer for lights. If you have an old trailer and want to replace everything, I recommend using a kit like our Peterson Tail Light Kit, # 432800 and our trailer wiring installation kit # HM51020. We also have an LED kit, # TLL9RK. Step 1 - The trailer connector should extend 2 - 3 feet past the tongue. Attach the ground wire directly to the tongue of the trailer using a self tapping screw # 101131802 and a ring terminal...
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  • Troubleshooting 4-Pole Trailer Wiring Harness After 18-Months of Use
  • The Tow Ready T-One wiring harness you referenced, part # 118566, is indeed very similar to the 4-pole wiring harness you purchased from etrailer in October 2013, which is part # C56164 from Curt. Thank you for that purchase and also for your hitch purchase. A 4-pole wiring harness such as what you have carries power only for the trailer's stop, turn and tail lights. The problem you are having with all trailer lights staying on continuously once the trailer is plugged in to the Escape...
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  • How Does the 35 Foot Wishbone 4-Way Trailer Wiring Harness # A35W42B Function
  • The way that the 35 foot Wishbone 4-Way Trailer Wiring Harness, # A35W42B, works is instead of having 1 taillight wire (brown) that you would need to splice into in order to run to both taillights, this harness has two wires (one attached to each stop/turn signal wire). The wires are attached to each other (except at the 4-Way connector) so you cannot mix them up. This would be good for your application since you will not have to splice wires that could end up being exposed to the water....
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  • Wiring Trailer Stop, Turn, Tail and License Plate Light, # ST9RB to a Trailer
  • When wiring Trailer Stop, Turn, Tail and License Plate Light, # ST9RB, how you wire it depends on the type of wiring harness you have on the trailer. If you are using a 4-Way flat that includes one tail light wire, you will need to attach a jumper wire to go from one light to the other for running lights like you have described. There is also what is called a wishbone harness, like # A35W42B. This type of harness has the tail light signal split at the plug. There are then two separate...
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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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  • Parts Needed for Custom Wiring a Trailer For Separate Turn and Brake Lighting
  • In order to have separate turn and brake lights on your trailer, I strongly recommend using a 2-wire to 3-wire converter, like the Tow Ready # 118158 on the trailer. This will allow you to have 4-way connectors on both the vehicle and the trailer. The 4-way connectors are much more common than 5-way connectors, and will allow to you tow other things with your vehicle, or tow your trailer with other vehicles, without the need for an adapter. This converter box is not designed to be exposed...
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  • All Trailer Lights Blink With Turn Signal on 2007 Triton ATV Trailer
  • The fact that you have an aluminum trailer could be the problem. Aluminum does not make for a good ground. What I recommend is to located the ground wires at the backs of the lights and attach jumpers from the grounds to the main trailer connector ground. This is a common issue with aluminum frames, tilt trailers, and trailers with folding tongues. Also check the towing vehicle and trailer connectors for dirt and corrosion. Corrosion could cause a short or even a bad ground as well. The...
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Expert Research:
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Expert Research:
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Jameson C

Expert Research:
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Expert Research:
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Expert Research:
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Expert Research:
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Expert Research:
Victoria B

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