Videos are provided As a guide only. Refer To manufacturer
installation instructions And specs For complete information.
Item # A35W42B
Orders above $99 qualify for free shipping
Shipping Weight: 1.3 lbs
This is a 35' split wishbone 4-way trailer wiring harness with four conductors and a 42" ground wire.
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
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.
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.
Average Customer Rating: 4.8 out of 5 stars (204 Customer Reviews)
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
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
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
Perfect description, Amazingly fast delivery, Wonderful communication. Will for sure be shopping here again. 225773
Worked great, I had a hard time finding wire in the length that I needed. Was easy to install. 220248
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
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
Top quality, perfect length, simple wire harness. 224248
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
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
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
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
by: Gino, Jr.08/19/2014
Excellent product no hassle installing! 147313
by: Randy S06/20/2014
Great fit for my boat trailer!! 136721
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
by: Jim C05/13/2011
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. 13795
by: Jim C05/13/2011
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. 13794
by: Ray R05/20/2013
I received 2 of these wiring harnesses and wired my utility trailer and boat trailer in less than 2 hours after receiving them. The video was very helpful great product. I will be using etrailer from now on. Thanks folks! 81088
by: Bill T.03/30/2012
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. 35648
by: Jon B09/22/2016
I've made 2 purchases from etrailer.com in the past 3 weeks. Shipping was fast, the price was competitive and all items purchased were as stated in the descriptions. This is my go to site for any of my future needs. 300083
by: Barry S03/03/2017
Product was received in good condition and was exactly what I ordered. No hick-ups or other issues. Quality of the product was good as expected. I would have no issues with ordering from this company again. 351336
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