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Running lights down both sides of a trailer usually means extra splicing or jumper wires, but this 35 Ft 4-Way Wishbone Trailer Wiring Harness makes it easier. It splits the running light circuit into two brown wires so you can run one down each side. That saves a lot of time and keeps everything neat without crossing wires from side to side.
If you’ve ever come up short halfway through wiring, you’ll appreciate the full 35 feet of length on this harness. It works well even for long flatbeds or boat trailers, and any extra wire can just be trimmed down when you’re done. You get room to route wiring cleanly without stretching or patching extensions.
Hook-up is straightforward with the standard 4-flat configuration. The green wire handles right turn and brake, yellow is for left turn and brake, the brown pair runs the tail and marker lights, and the white wire provides ground. Each color follows standard trailer wiring layouts so you can match them up quickly during install.
Each of the four wires in the harness uses 20 AWG copper strands for flexibility and dependable signal transfer to your lights. The white ground wire comes at a 42" lead, giving you enough reach to find a clean ground point on the trailer frame for a solid connection.
Whether you’re rewiring an old trailer or starting fresh, this universal splice-in harness fits a wide range of setups. It’s an easy way to replace damaged wiring or convert from a different connector style while keeping a standard 4-flat connection ready to plug in at the hitch.
Customer Satisfaction Score:
99% were satisfied with this product
1% of customers were not satisfied
Ratings & Reviews
Impressed that I was given the names of everyone involved in my purchase start to finish and how to reach them if need be. etrailer has great communication at every step of the way. Order promptly processed, picked, packaged and shipped. Very pleased as items arrived in perfect condition Thanks everybody!
Quality product and well made
I actually ended up using this to wire up a towed/TOAD vehicle for behind my motorhome.
I cut the four pin connector off and just used it pretty much just for the colored wires, but it was good quality nonetheless.
The 35 ft. Trailer Wiring Harness was the perfect solution to completely rewire my boat trailer. One of the power supply wires on my old wiring harness shorted out and melted a section of the wire that run through the inside of the trailer channel. I also had other connecttions that corroded over the years due to putting the trailer in salt water. The videos on etrailer were a big help and I was able to do the job myself.
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!
Perfect fit for my 20' Pontoon trailer wire replacement. Quick and easy. Only wish there would have been a heavier gauge option available as I would have paid extra for one!
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.
Absolutely Fabulous! Exactly what I was looking for but couldn't find at any retail store in my area! The wishbone design splits the brown wire at the plug. Makes wiring both sides of the trailer with no splices or having to find additional brown wire sold by the foot!
Great product
2 things. 1st@: I think there should be an option to pick tinned wire. 2nd: The ring terminal for the ground needs to be bigger.
Castaway
6/14/2024
Works as it should.
Just what I needed,works great
It was easy to order, and there was a nice selection. Shipping was reasonable and quick.
Bud
8/2/2025
Its working just great, no problems.
The wiring harness works great.
This worked great, had to rewire my trailer after having it painted and reconfigured and this item was long enough and allowed me to tie in my additional lights.
The products were in stock and delivered on time even during holiday period!! Great job
This is the answer for damaged old trailer wiring. It eliminated the excessive splices and taped repairs that were on the old wiring.
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!!!!
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!
Eric
1/29/2019
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.
Certainly makes replacement much easier. The customer service is world class!
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.
The story behind this order. My dog loves chasing chipmunks, chipmunks love going into holes,especially into the tubing holes in my trailer. The wiring was in the way so my dog made the wiring go away very enthusiastically. Hence the order for a new harness, wire loom and connector cover.
Very easy to order from this site and the product looks great and was delivered on time . Thanks
Ray
8/17/2025
Working great
Perfectly executed with the connector and wires going the length of the trailer and splitting off to each light.
Wure Harness worked great for my application.
Side marker yellow LED lights look great at night.
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Heather A.
3/19/2025
Looks great Michael! Thanks for sharing your install photo with us.