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The Best Boat Trailer Wiring Harnesses

Written by Anthony Roberts / Fact checked by Jonathan Larson

It may be a real hassle to have dysfunctional wiring harnesses in our boats. This leads to failing brake lights, taillights, and turn signals. When these instances occur, it’s high time to replace your old wirings.

best boat trailer wiring harness

Always remember that the market offers a wide selection of available harnesses, making it hard to find the best boat trailer wiring harness out there. Fret not. If you’re on a mission to get a brand-new wiring harness, you can begin by reading through our list of product options wisely chosen below.

<strong>Top 1</strong>


+ SAE J1128 standard
+ The ideal trailer wiring harness
+  Convenient setup due to its wishbone design

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<strong>Top 2</strong>

SUZCO Wiring Harness

+ The item is extremely lightweight
+ A rust-proof harness
+ A clear manual makes assembly easier

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<strong>Top 3</strong>


+ The core is made of pure copper
+ It comes with a PVC with a UV coating
+ Two-year warranty

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Top 12 Boat Trailer Wiring Harness Reviews

1. ONLINE LED STORE Flat Trailer Wiring Harness

Take your worries away with this boat trailer wiring kit that comes with both male and female edges for extra value. This SAE J1128-rated product has a minimal voltage main cable, fully intended for a low system voltage of 60 V DC. Check out more about this amazing product.

It is the ideal marine trailer wire for trailers under and over 80 inches wide, thanks to its length of 25’ plus 4’. Besides that, it comes with a wishbone design wiring setup that I find handy. This feature makes it more convenient to wire the taillights and therefore streamlines the setup process.

Another feature that makes it easy to install is its 18 AWG colored wires that allow for quick recognition of each wire’s function. Because of them, I never got confused while installing the harness anymore, allowing me to assemble it safely and quickly.

However, do take note that this product does not have a very long ground wire. Thus, you might have to splice it a little to make things work. I don’t see this as a big problem, because the kit does its job well otherwise.
  • Comes with both male and female edges for extra value.
  • SAE J1128 standards for low voltage main cables.
  • The ideal trailer wiring harness for trailers under and over 80 inches wide.
  • Guarantees a convenient setup due to its wishbone design.
  • The 18 AWG wirings add up to its easy installation.
  • The ground wire is not very long.
Try out this remarkable product if you want to make your electrical systems safe and secure. Plus, it is never a hassle to install. Make your life easier with this boat trailer wiring harness kit.

2. SUZCO Flat Trailer Light Wiring Harness

If you’re looking for a functional boat trailer wire kit, SUZCO is a reliable brand to try out. This company has been manufacturing reliable automotive equipment that makes both land and water adventures more enjoyable. Take a look at SUZCO’s incredible product.

This lightweight item is a 25-foot male and female boat trailer harness with four-way conductors and a white ground cable. I love how it’s made of 18-gauge wiring, dividing the trailer tongue and running down on each side of the trailer. Its four-way boat trailer wiring connectors make for a basic lighting hookup, too.

Plus, this marine trailer wiring harness is color-coded and comes with fused cables. Therefore, it is easy to splice into the trailer’s wiring system. Another feature that I find handy is the sealed, rust-proof construction of this item. Its wiring instructions also make my work easier.

Moreover, the company provides a two-year warranty, so that should give you some peace of mind when choosing its wiring harness.

As for setbacks, this product doesn’t come with clips for wire securing. I was able to use the old ones I already had, but if you don’t have some ready, you will have to make another purchase.
  • The item is extremely lightweight.
  • It promises a basic lighting hookup with its four-way connectors.
  • Color-coded and fused wires make it easy to splice into the trailer’s system.
  • A rust-proof harness.
  • A clear manual makes assembly easier.
  • A two-year warranty included.
  • Clip for securing wires not included.
This product is definitely something to try. If you want to make your task easier, check this one out for a change. Plus, its rust-proof feature adds to every user’s convenience.

3. CZC AUTO Trailer Wiring Harness Kit

It may come as no surprise that excellent trailer harness kits come from long-lived brands such as CZC AUTO. They make their products with only the superior materials available, such as a copper core for their boat trailer light connectors. Keep scrolling to learn more about this phenomenal product.

PVC and anti-UV materials cover this item’s core to ensure optimum durability. Its PVC boat trailer plug has copper terminals plated with nickel, making it efficiently sealed and rust-proof. I don’t have to get worked up about submerging it in water for an extended period. It also comes with a two-year guarantee given by the company.

This almost 30 foot boat trailer wiring harness is lengthy enough for every kind of 12V trailers with 4-pin connections. It also comes with a wishbone structure with four female plug wires and five male connectors. Plus, two pieces of brown working lines split from the trailer lights for a simple connection.

Overall, I have no complaints about this product. However, one customer reported not receiving the clips in the package. If you’re worried about missing items, the company does have a 30-day money back guarantee to give you peace of mind.
  • The core is made of pure copper.
  • It comes with a PVC with a UV coating for optimum durability.
  • The copper terminals with nickel plating make the item sealed and rust-proof.
  • Comes with a two-year warranty by CZC AUTO.
  • Lengthy enough for every kind of 12V trailers with 4-pin connections.
  • 30-day money back guarantee.
  • A case of missing clips.
If you want to replace your harness with a reliable one, try this one out for a change. I like the corrosion-proof feature that makes it more durable. Besides, the warranty makes my purchase risk-free.


It’s high time to invest in a trailer harness that effectively meets your demands. This harness is thirty feet in length, allowing you to cover trailers extensively. It is an ideal wiring kit, whether it’s for maintenance or re-wiring purposes. So, check out this incredible harness for your boat trailer.

This 4.8-ounce product comes with a wishbone design for more comprehensive use. The product’s two smooth brown wires allow you to cover two boat trailer lights at once. The terminals are also rust-proof, so I don’t have to worry about the item corroding off.

Aside from all the mentioned features, I also love how this product is surprisingly convenient to use. I never had a hard time using this flat trailer harness. Plus, its installation is also a breeze. This feature allows me to spend fewer hours trying to assemble the product.

Although I had no problem setting up the kit, one customer had a problem working out the split cord design, making the lights or turn signal inconsistent. If you have the same experience, you can watch the instruction video from the manufacturer or contact Hopkins.
  • 30-feet long wiring can cover trailers more extensively.
  • It is the ideal harness kit for maintenance or re-wiring purposes.
  • The terminals resist rusting or corrosion for a more durable product.
  • This harness is surprisingly easy to use.
  • A wishbone design.
  • Convenient and quick installation.
  • Some users might have a problem with the split cord design.
Overall, this flat trailer harness is something to try. I love all of its handy features that make my work easier and quicker. If you want to make your boat connection secure, check this one out.

5. CURT 58030 4-Pin Flat Wiring Harness

This item from CURT is one of the high-quality harnesses that you can see in the market. It guarantees an easy grip. I love how I can plug in my boat trailer wiring kit with led lights conveniently, thanks to the ergonomic design of this boat trailer wiring plug. It also comes with top and bottom tabs that guarantee better installation grip.

This product guarantees reliable connectivity, thanks to its 4-pin wiring plug that can readily connect to my current trailer wire. Plus, its 16-gauge cables efficiently attach to the taillights, brake lights, and turn signals. If you’re particular about structures, fret not. Its versatile design makes it a great replacement for your old wiring connector.

The design suits the industry’s standard 4-way flat sockets, making it compatible with a wide variety of trailers. Its durable construction that stems from sturdy black molded rubber guarantees a corrosion-free harness. You can have it installed anytime, thanks to its blunt-cut, 12-inch cable and color-coded wires.

As for setbacks, I received the wrong connector upon arrival. I noticed that the manufacturer sent me a male side upon installation, which was not compatible with my vehicle. Thus, I had to return the wrong connector and get a replacement.
  • The ergonomic design allows for convenient plugging.
  • It has top and bottom tabs for better installation grip.
  • This product guarantees reliable connectivity due to its 4-pin wiring plug.
  • Comes with a versatile design, making it a great replacement for old wires.
  • A corrosion-free harness that promises convenient installation.
  • Wrong part sent.
This remarkable wiring harness is something to try if you want a reliable connection for your trailer. Plus, it comes with an attractive and versatile design. Try this one today.

6. WESBAR 702275 Flat Trailer End Wire Harness

Are you one of those people searching for the right boat trailer wiring harness to make your trailer connection secured? Fret not. This harness is one of the products that you will undoubtedly be excited about upon reading its features. Keep scrolling for more.

This item is crafted only from the finest durable materials to give you a top-notch product. It is highly compatible with all five-flat automobile connectors, so I never experienced any hardships installing it on my trailer. Plus, the split wire allows me to get the wirings from the connector to the taillight.

The color-coded wires have a total length of 25 feet. There’s also a 4-feet ground wire that makes my hookup easier. Plus, no jumper wire is necessary for your tail lights, making this item even more convenient. I love how it conforms to the SAE J1128 interface specifications. And because Wesbar products are waterproof, you won’t have to worry too much about durability.

Overall, this item works well for my needs. I just wish it came with a dust cover. That, coupled with the one-year warranty from Wesbar, would have made this harness perfect in my eye.
  • The product is crafted from the finest durable materials for top-notch quality.
  • Highly compatible with five-flat automobile connectors.
  • The split wire feature allows for efficient wire running from connector to taillight.
  • Easy installation with colored wires and ground wire, no jumper wire necessary.
  • It perfectly conforms to the SAE J1128 interface specifications.
  • Comes with a one-year warranty.
  • No dust cover.
Try out this salt water boat trailer wiring if you want to make your trailer connection safe and secure. This harness offers premium quality that guarantees to keep my boat trailer functional.

7. SHORELINE MARINE 4-Way Trailer Wire Harness

Everyone wants to keep their trailers fully functional and in top condition. If you’re searching for the ideal wire harness, this SHORELINE MARINE model might be what you need. This is a good brand when it comes to manufacturing marine equipment to meet your adventure’s needs. Take a look at this terrific product from them.

This four-way saltwater trailer wiring features a 25’ wishbone design for more compatibility and better coverage. Besides that, I also love how it comes with a 4’ vehicle side connector that further enhances the trailer handling. These features guarantee a proper connection to my trailer.

As for its convenience, I appreciate the color-coded wires that come with frame clips. This ensures that my installation goes as smoothly as possible. Plus, the clips free me from confusion by letting me sort out and tie the wires down. The wire connectors can also be clamped together, which guarantees swift lighting assembly.

However, it’s best to protect the wirings with grommets because their casing is not very thick. Other than that, using this wire harness is as trouble-free as it can get. I had no problem pairing it with my trailer.
  • This four-way trailer wire harness offers optimum compatibility.
  • The product comes with a 4’ vehicle side connector that enhances handling.
  • Color-coded wires make your installation clear and free from confusion.
  • This harness’ frame clips further make the installation smooth and quick.
  • Wire connectors can be clamped together.
  • Wire casing is not very thick.
This reliable trailer wiring harness makes every penny worth it. It is long-lasting and connects to your trailers effectively like magic. Investing in this harness is a good decision that won’t leave you with any regrets.

8. ABN 4-Way Hitch Light Trailer Wiring Harness

We all want a harness that works well with our trailers. However, choosing and buying one is challenging. This product from ABN offers effortless trailer wiring that keeps you comfortable and unconfused throughout the installation process. Keep scrolling to know more about this product.

This harness comes with a 4-feet trailer wire extension and a four-way four-pin flat 20 gauge. You can use this boat trailer plug adapter for your hitch light trailer wiring. I love all this equipment as they efficiently assist me in making my trailer functional. The accessories also help me extend the truck to the trailer wires.

Thanks to its high compatibility, this wiring device is applicable for various uses. The versatile ends make it ideal for an array of trailers, whether these automobiles are made for marine vehicles, horses, motorcycles, or ATVs. Plus, I don’t have to splice the wires, making installation easier for me. The harness also comes with durable color-coded wires for optimum ease.

I don’t really have any serious complaints about this product, just a tip. In my experience, it’s better to use zip ties for securing the wires. Bungee cords also work, but not as well.
  • This product comes with an extension and a gauge.
  • Suitable for hitch trailer wiring.
  • Offers high compatibility with many trailer types.
  • No need to splice wires.
  • This harness comes with highly durable color-coded wires.
  • Zip ties should be used to secure the wires.
To sum it up, this kind of boat trailer wiring harness is the best choice for me. I love all of its useful features that make my work easier. If you’re mostly busy like me, this product is worth it.

9. NILIGHT Heavy Duty 7-Way Inline Trailer Wiring Harness

Suppose you are in search of a durable wiring harness that will last a long time. This item from NILIGHT is a good option to try out. Experience luxury with this wiring harness that makes your work easier. Know more about this product and why people see it as a good investment.

This harness is equipped with a 7-way copper blade for sturdiness. It is molded into a highly robust plug that offers a swift and straightforward way of connecting wires. It also comes with a handy and durable trailer wiring junction box that can help keep your equipment in order. These features made installation trouble-free, even for a beginner like me.

I also love its 8 feet extremely flexible connection cord that comes with durable PVC housing. This harness allows me to obtain a flexible connection that comes in handy, whether I use it for turn lights, reverse lights, for RVs or campers.

This reliable harness also has an incredible sealing performance that makes it highly durable. The four open and four close-sealed rubber gaskets make the whole product water and dust-resistant.

However, to avoid qualms in buying this product, make sure it perfectly fits your needs. I have only tried it on an electric brake system, so I’m not sure how well it works as boat trailer wiring with surge brakes.
  • It is equipped with a 7-way copper blade and rubber gaskets for sturdiness.
  • A highly robust plug that offers swift and straightforward wirings.
  • Comes with a handy and durable trailer wiring junction box for tidiness.
  • Guarantees no troubles with installment, even for a beginner like me.
  • It has an extremely flexible PVC connection cord that’s 8 feet in length.
  • Works with many lights and vehicles.
Overall, I prefer this one-of-a-kind product as it made my wirings more organized and fully functional. Trust me when I say that this incredible product stays true to its words. Truly a must-try!

10. MICTUNING Trailer Wiring Harness Kit

Worry no more as I introduce this remarkable harness kit from MICTUNING. This 4-Way Trailer Wiring Harness comes with 25-foot male and 6-foot female parts. I love how I can conveniently install the trailer through these 4-Way connectors. They are easy to splice into, so I can have the kit working in no time.

I can keep my lights fully functional with this harness as it effectively supplies and distributes power. Plus, the ground connection is also consistent. The wishbone design wiring setup makes it quicker to connect to the taillights, giving me more time to do recreational activities. For ease, the running lights are also split into two wires.

Since this is a universal product, I can use it with any trailer under and over 80 inches wide. This product is also ideal for all kinds of trailers, whether they’re used for marine boats, motorcycles, ATVs, or other utility trailer hitches. It is one of my favorite harness kits on the market.

The only aspect that I don’t like about this product is its short ground wire. It is not a problem if you’re near the connector, but if you need something longer, this kit is probably not the best choice. Other than that, it’s good to go.
  • Four-way trailer harness that comes with both male and female parts.
  • This product is extremely convenient to install.
  • Effectively supplies power.
  • The wishbone design wiring setup makes it quicker to install the taillights.
  • This product is universal, making it usable and suitable for all types of trailers.
  • The ground wire is short, so it might not suit everyone.
To wrap up, this boat trailer wiring harness is worth your money. It is a high-quality product for me. Plus, I love all the unique features that come with this harness. This product is worth a try!

11. EXERAUO Trailer Wiring Harness Kit

If you’re one of those people who’s particular about your harness, check out this one from EXERAUO. It is made of the finest materials that pass quality inspections to give steady performance and reliability. Keep scrolling if you’re curious about this incredible harness kit.

The wirings have lengths of 25 feet for the male part and 4 feet for the female part, allowing for more extensive coverage of your trailer. Aside from that, the extension kit comes with eighteen AWG colored wires to give me a safe and simple wiring experience. Its high versatility makes it ideal for trailers below and above 80 inches in width.

In total, this corrosion-resistant trailer wiring harness kit includes double wiring harnesses with four smooth connectors for convenient setup. I love how this feature also prevents tangling wire instances during installation, thus, reducing my wiring time. Plus, the company provides a 30-day return or replacement service, making it risk-free to try its products.

Despite being rust-proof, the wires are a little bit flimsy. So, I have to take extra good care of this wiring harness for it to last longer. I love all its features, though. The installation is also a breeze for me. Other than its fragile wiring, this product is good to go.
  • Made of the finest, materials to deliver steady performance and reliability.
  • Wire lengths of 25 feet male and 4 feet female offer more extensive coverage.
  • 18 AWG colored wires keeps the wiring procedure safe and simple.
  • For all trailers more and less than 80 inches wide.
  • Double wiring harnesses with connectors make the setup convenient.
  • This anti-corrosion product comes with a 30-day replacement and return service.
  • The wires are a little bit flimsy, so extra care is needed.
In summary, this super convenient harness is a must-have product for everyone. It is one of the best models out there. With all its handy features, I can spend less time installing it. I can’t find a better product than this.

12. NILIGHT 4-Pin Flat Trailer Wiring Harness Kit

Check out this remarkable trailer wiring harness kit from NILIGHT. This product comes with eighteen AWG wires. The male piece is 25 feet, while the female one is 4 feet. The two have an electrical ground wire that is extremely handy. Plus, these wires are created to divide at the tongue of the towed vehicle and run on each side for extensive coverage.

This kit delivers the finest current conduction thanks to its high-quality copper wiring with tinned plating. Aside from that, this tinned trailer wiring harness comes with an anti-oxidation feature, along with its first-class PVC layer for the finest rust-proof and age-proof capability. It can withstand seawater harshness with no breakage.

Plus, its four-way connector has a commendable design that makes it easy to plug. Each wire is represented by a vibrant color, too! I find it handy because I can easily route it into my hauler’s cabling system and attach it with lights. This universal harness is usable on trailers below and more than eighty inches wide.

This wiring harness comes with all the handy features you’ll need. What’s surprising is that I couldn’t find any negative reviews for this item. This rarely ever occurs during my search for products, so it’s especially notable when it happens.
  • Comes with 18 AWG connector wirings and a full ground wire.
  • Designed to separate at the trailer tongue and run down for extensive coverage.
  • It delivers the finest conduction thanks to the copper wire with tinned plating.
  • The anti-oxidation feature and PVC coating make it rust-proof and long-lasting.
  • This universal harness is usable on trailers below and over 80 inches wide.
  • Easy-to-plug design with recognizable wires.
  • None found so far
If you have difficulty deciding the best product to use in your trailer, worry no more. I strongly suggest this harness because all of its features are highly reliable. Try this product now.

Buyer’s Guide


Before getting yourself a new trailer wiring harness, it won’t hurt to know a little info about this item. A trailer harness links your vehicle’s electric arrangement to your trailer’s electronic part. A properly wired one illuminates your trailer lights while you’re using your automobile.

It helps other drivers notice your lighting, which is not only a rational safety tool but are also the law. So, what type of cabling harness do you find essential? And what are the things to remember when having yourself a new harness?

The plug or socket type, the amount of pins on the harness, and the wiring configuration are necessary factors to consider.

Plugs and sockets are connections that enable you to link your trailer and your automobile. There’s a wide variation of their shape, but flat, circular, and RV blades are the usual choices.

Aside from the plugs and sockets, the number of pins on the harness is also important. The standard trailer connectors come with four to seven pins. It’s important to note that the greater the number of pins, the more roles it can have. It would be best to refer to a 4 way trailer wiring diagram for the functions.

One pin serves as a grounding system on every connector. Thus, a four-pin joint can hold three functions and controls the key lights. Similarly, a five-pin socket can have four functions. Upgrading to a connector with five pins either adds the backup lighting or power-assisted brake. It’s important to note that this endeavor is also affected by the plug.

You should refer to a boat trailer wiring schematic to learn about the wishbone and crossover harness types. Most boat trailers have a wishbone wiring harness or a split Y harness. This separates the functional gleam circuit at the trailer’s joint so that there’s no need to run a jumper wire from one taillight to the other.

The crossover type, which is less popular, has wiring on one side of the trailer. The wires are also positioned across and between the tail lights.

How Do I Protect My Boat Trailer Wiring

The best way to protect your boat trailer wiring is to keep it covered. It’s also a good habit not to fully rely on the corrosion-proof feature of your harness. Therefore, applying some Dielectric grease for electrical connectors will help. This tool can further assist you in eliminating corrosion, making your connectors more secure.

What Gauge is Boat Trailer Wire


A typical 4-way trailer wiring consists of 18 and 16 gauge wires. Some parts use 18 gauge, while there are also ones that utilize the 16 gauge. The trailer wires that use 16 gauge are usually the white ones.

How Do You Prevent Trailer Wires from Corroding

When you put on a brand new connection, it’s best to coat the bare metal exterior with dielectric silicone grease. This thing keeps moisture off, which slows down corrosion. You can also put the stuff into the connector. This part might be messy, but it is proven to resist rusting.

How Much Does It Cost to Re-wire a Boat Trailer

Re-wiring a trailer is the process of removing the old wires and trailer lamps, directing the brand-new cabling harness through the structure, installing new trailer lights, and testing the lights.

This process may be costly. Most shops charge $90-$110 per hour. So, a day of wiring will cost you about $800 for the labor alone. Plus, re-wiring a boat would usually take up to two weeks.

However, you can have a DIY re-wiring by following these simple steps and a boat trailer wiring harness diagram at home. This part walks through the steps required for rewiring trailer lights. Plus, you can use it to re-wire all types of trailers.

The first step is to make a simple sketch of your trailer on a sheet of paper. To make your plan clearer, plan and label the different cables’ layout through the frame, including each wire’s color. This guide comes in handy, especially when it’s time to connect the new hauler cables and re-wire lights.

Next, get rid of your previous trailer wires and running lights by unscrewing the parts and cutting the cables attached to the frame and the lights. Remove the cables from the hauler structure, starting from the back portion to your trailer’s front. If the wires pass through an enclosed part, use previous wirings as a guide to simply yank the new cables through.

Direct the new wiring to the hauler’s rear. This is the part where the sketched diagram becomes useful as a guide. The yellow cable, as well as the brown-colored ones, should go to the driver’s area. At the same time, the green-colored and brown-colored ones should belong to the passenger’s part. The white one should stay close to the hauler’s tongue.

The next step is to ensure you keep an equal cable length on every side of the trailer. Besides that, leave extra wires at the front for working into your automobile. Splice the white ground cable’s end and get rid of the previous cable’s ground bolt. Cover the bolt with the copper cable and secure it properly.

Set up new marker lights with the bolts. To make your work easier, you can use the established holes. After you have secured all the lights, you can then attach the light cables to the hauler’s electrical system.

Fasten the hauler cables onto the structure, starting from the head to the rear. Ensure firm attachment of trailer wiring; make sure it’s sheltered well by the trailer frame and away from moving objects and highway debris.

The next thing to do is set up the tail lights. Position the lights appropriately, then strip the ends of the trailer wires. Also, add the wires into their proper connection points. With the wires securely linked, secure the rear lamps onto the hauler’s structure.

Lastly, ensure that your new lights are fully-functional. Attach the trailer to your automobile and try to check if the lights synchronously work. You can achieve this by testing the brake lights, turn signal lights, and running lights. Now you’ve successfully replaced your old wirings with a new one.


It’s undeniable that the market offers a wide range of good quality wiring harnesses. However, our article carefully filtered out the best of the best boat trailer wiring harness. It can help you choose the ideal one without getting confused by other products out there.

So, carefully choose your product and start replacing your old ones. By doing so, you can bring your boat trailer back to life again and make your work easier than ever. The convenience it gives helps you enjoy life a little more. Besides, you also can refer more to boat trailer guides to guide your boat better.

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