The Ultimate Guide to Buying Boat Trailer Lights

Faulty boat trailer lights can put a damper on any fishing trip, especially if you get pulled over and ticketed. Having been there first hand, we know how frustrating the experience can be. We received a ticket when leaving a boat ramp that was only a couple miles from our house. 

We're going to walk you through how to find bullet proof boat trailer lights that you don't have to worry about failing, and also the minimum legal boat trailer lighting requirements for your particular boat trailer. Boat trailer lighting is a unique investment where if you buy a quality set the first time, them not going out and resulting in a ticket will save you a ton of money in the long run. 

What Makes Quality Boat Trailer Lights?

Enhanced Waterproofing for Submersible Trailer Lights

Marine Grade Wiring for Corrosion Resistance

Durable Housing that Lasts

Legal Lighting Requirements for Boat Trailers

Typical Boat Trailer Size Based on Boat Size

Less than 80" Wide, Less than 30 ft Long

80" Wide or Greater, Less than 30 ft Long (most common)

Less than 80" Wide, Greater than 30 ft Long

80" Wide or Greater, Greater than 30 ft Long

SAE Lighting Identification Codes for Boat Trailer Lights

 

What Makes Quality Boat Trailer Lights?

As stated in the legal lighting requirements for boat trailers, boat trailer lighting is governed by a variety of SAE codes which describe the functional requirements of the lights. That being said, some lights may achieve a single function while others are designed to achieve multiple functions. The problem among boat trailing lighting is rarely the functionality, though.

The problem with boat trailer lighting is typically discovered after a long fishing trip on your way home from the boat ramp, you get lit up and pulled over by the local law enforcement to find out your boat trailer lights went out. This may be due to corrosion, a poor quality light, or something else. 

There are three (3) main design features that can help your boat trailer lights last for the long haul:

1. Enhanced waterproofing for submersible trailer lights
2. Marine grade wiring for corrosion resistance
3. A durable housing that lasts.

As crazy as it sounds - these features are rarely (if ever) implemented into today's standard trailer lights.

Enhanced Waterproofing for Submersible Trailer Lights

In terms of boat trailer lighting, waterproof and submersible carry two different meanings.

Difference in "submersible" trailer light and "waterproof trailer light"

• A submersible light will let water in, but has drain holes for the water to go back out.
• A waterproof trailer light is completely sealed to keep water out. 

Which last longer?

• Submersible trailer lights will have problems with corrosion on the contacts over time because they are being exposed to water every time you back down the boat ramp.
• A truly waterproof trailer light should not have those problems, but most do - and I'll explain. 

The majority of waterproof trailer lights out there are manufactured by "sonically sealing" the trailer lights.

What are sonically sealed trailer lights?

• Directed sound waves are used to accelerate the molecules (causing heat) to eventually melt the plastic together so it behaves as one continuous piece. (sonically sealed plastics can be compared to using a microwave to heat up meals)

The problem, though, is the plastic is made from a thin polycarbonate that can get hairline fractures from the vibration associated with hauling a boat trailer. Boat trailers have leaf springs, they don't have suspension like cars. 

How do we solve these problems?

Our solution is something we actually pioneered, tested, and proved with our underwater green fishing lights and our Swamp Eye Submersible flounder gigging lights. We developed an optically transparent cured-in-place compound with adhesion levels that rival super glue, which allows us to fully encapsulate LEDs.

In other words, we are able to completely encapsulate a trailer light so no matter how much vibration it encounters, it will always be sealed. This eliminates the hairline fracture problems with current waterproof lighting and it also eliminates the contact corrosion issues submersible trailer lighting experiences. 

Marine Grade Wiring for Corrosion Resistance

The majority of boat trailer lights come standard with open copper wire. Anyone who owns a boat and has dealt with wiring issues on their boat before, knows that bare copper wire is something you must avoid unless you want to deal with continual corrosion and loose connection issues.

It is best to use tinned marine grade wire. This type of wire has supreme corrosion resistance to help minimize problem associated with trailer lights.

One of the most common problems is done during the installation process and people don't even know it. They use thinly coated trailer wiring (because manufacturers are not required by the government to use any different) and when they mount it to their trailer frame, the thin coating cracks. Inside, the wire is bare copper. Initially, you won't notice any issues. However, after backing your trailer down the boat ramp several times the water will penetrate through the crack and the low voltage will cause electrolysis which will, over time, slowly disintegrate the wire. This problem is extremely hard to detect because you have to literally inspect the entire trailer harness to find it. 

How do you avoid this? Well, purchase a trailer harness that comes with quality marine grade tinned wire that is durable. All it takes is avoiding getting a ticket one time and it will pay for itself. 

Other key points:

• NEVER use wire nuts on boat trailers. The only method of connecting trailer light wiring that will hold up for the long haul is with solder-seal waterproof wire connectors or by soldering the connection yourself and covering it with adhesive heatshrink. 
• If possible, it's best to run a ground from the tongue of the trailer and then connect the trailer lights to that ground. The tongue of the trailer will not be submerged (or if it is, you have bigger problems) so problems associated with bad grounds due to corrosion are less likely. This is opposed to how most trailer lights will ground at the point they are mounted - this usually results in grounding issues down the road that cause the lights to not work or flicker. 

Durable Housing that Lasts

As we previously mentioned, most trailer lights are made from a thin polycarbonate or acrylic material which rarely holds up well for the long haul. The material can often degrade with UV exposure, which when combined with constant vibration results in hairline fractures and lights that cease to exist as water penetrates into your wiring and connections. 

It's best to go for a strong and durable housing that will actually stand up to UV exposure as well as saltwater or freshwater. These are typically made from a high grade of polycarbonate with a UV additive or an aluminum housing. In our experience it is best to avoid acrylic or "PMMA" materials for trailer light housings. 

Legal Lighting Requirements for Boat Trailers

The Department of Transportation (DOT) governs the rules and regulations for what is required on boat trailers. The National Highway Traffic Safety Association (NHTSA) establishes and enforces the Federal motor vehicle safety standards (FMVSS) which ultimately dictate what lighting and reflector you are required to have on your boat trailer.

Finding out what these actual rules and regulations are, however, is not so easy. We spent a lot of time sifting through their website, calling them on the phone, being transferred from one department to the next until we were finally referred to the Federal Motor Carrier Safety Administration (FMCSA) who provided us a little more clarity on what is required. The FMCSA link above will give you what they gave us - a link that goes to a ton of information. We also coordinated with the Department of Public Safety (DPS) who helped us better understand what lights are required on different length boat trailers. The DPS is over the State of Texas, but their rules follow DOT requirements.

In an effort to help people like us out, we have created a quick guide as it pertains to boat trailer lighting. Most information out there is for general utility trailers and semi trailers, but there isn't a lot of information on boat trailers. Here are some of the minimum lighting and reflector requirements for boat trailers of various sizes. 

These are the minimum required boat trailer lights and reflectors. Backup lights that flood the area behind your boat trailer when you are backing the boat down the ramp or into your storage barn, etc. are not required but are highly recommended.

In the event there are things we didn't cover or there are new laws put into place that may make this outdated, we encourage you to contact the NHTSA or your local motor vehicle office to ensure your boat trailer is legal. 

Typical Boat Trailer Size Based on Boat Size

Prior to getting started - you will want to know the size of your boat trailer. Here are some general boat trailer size estimates based on the size of your boat. The lighting requirements for your boat trailer will change depending on the size of your trailer, so it's important to know this information. 

It's best to measure your actual boat trailer rather than go by these estimations, and when you do - the length of your boat trailer must be measured at the longest point (hitch to the very rear), while the width of your boat trailer is measured at the widest point (outside the wheels). 

The widest a boat trailer can legally be is 8.5 ft, or 102 inches. As you can tell from this table, boats that are 16 ft long or greater typically have a boat trailer that is 80 inches wide (6.67 ft) or greater. You must go by the overall width. This is important to keep in mind when figuring out what boat trailer lights and reflectors you are required to have. 

Generally speaking, the length of your boat trailer is approximately 2 ft longer than the length of your boat. This is a generalization and can change for trailers with longer or shorter than normal tongues. 

Less than 80" Wide, Less than 30 ft Long

Boat trailers that are less than 30 ft long and less than 80 inches wide are typically for small boats that are generally no more than 16 ft long, as shown in the typical boat trailer size table. There are always exceptions so it's best to measure your trailer but this is a general observation we've seen. 

For boat trailers less than 80 inches in width and less than 30 ft in length, you are legally required to have the following:

Left Rear Trailer Light Requirements

• Red Stop / Turn Signal Lamp (SAE Code: S and I)
• Rear Red Reflector (SAE Code: A)
• Red Tail (Running) Lights (SAE Code: T)
• License Plate Light (SAE Code: L)

Note: These are all required to be mounted a minimum of 15 inches above the ground, except the license plate light. The license plate light does not have a required height.

Right Rear Trailer Light Requirements

• Red Stop / Turn Signal Lamp (SAE Code: S and I)
• Rear Red Reflector (SAE Code: A)
• Red Tail (Running) Lights (SAE Code: T)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

The SAE code is typically listed on your boat trailer lights. For this particular boat trailer that is less than 80 inches wide and less than 30 ft long, you can utilize one left rear trailer light that satisfies SAE Codes "S, I, A, T, L" and one right rear trailer light that satisfied SAE Codes "S, I, A, T". Another more common option is to use two trailer lights with "S, I, A, T" and purchase a license plate light SAE Code "L" separately.

We have found that license plate lights that tie into your license plate mounting bracket are more durable and trustworthy long term than lights that put a clear lens on the bottom of the tail light. These lights have a bad tendency to go out prematurely. 

Notable Exception

• If trailer is less than 30 inches wide (kayak trailer, for example), only one brake light, one license plate light and one rear reflector is required. These lights should be mounted at the center of the trailer and not on the outer edge. 

80" Wide or Greater, Less than 30 ft Long

The most common regulatory requirements we deal with are for boat trailers that are within these terms - 80 inches wide or greater and less than 30 ft in length. Boats that range in size from 16 ft long up to 27 ft long, as shown in the typical boat trailer size table, fall within these boat trailer lighting requirements. 

 

Boat trailers that are less than 30 ft long and 80 inches wide or greater are most common among recreational boats. The trailer lighting requirements for these boats fits most single and tandem axle boat trailers that range in boat size from 16 ft long and up to 27 ft long. These are general estimations, we encourage you to measure your boat trailer. 

For boat trailers greater than 80 inches in width and less than 30 ft in length, you are legally required to have the following:

Left Front Trailer Light Requirements

• Front Amber Reflector (SAE Code: A)
• Front Amber Clearance Lights (SAE Code: P3 or PC2)
• Front Amber Side Marker Lights (SAE Code: PC2)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

Right Front Trailer Light Requirements

• Front Amber Reflector (SAE Code: A)
• Front Amber Clearance Lights (SAE Code: P3 or PC2)
• Front Amber Side Marker Lights (SAE Code: PC2)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

Left Rear Trailer Light Requirements

• Red Stop / Turn Signal Lamp (SAE Code: S and I)
• Rear Red Reflector, Facing Side (SAE Code: A)
• Rear Red Reflector, Facing Rear (SAE Code: A)
• Red Tail (Running) Lights (SAE Code: T)
• Rear Red Side Marker Lights (SAE Code: PC2)
• Rear Red Clearance Lights (SAE Code: P3 or PC2)
• License Plate Light (SAE Code: L)

Note: These are all required to be mounted a minimum of 15 inches above the ground, except the license plate light. The license plate light does not have a required height.

Right Rear Trailer Light Requirements

• Red Stop / Turn Signal Lamp (SAE Code: S and I)
• Rear Red Reflector, Facing Side (SAE Code: A)
• Rear Red Reflector, Facing Rear (SAE Code: A)
• Red Tail (Running) Lights (SAE Code: T)
• Rear Red Side Marker Lights (SAE Code: PC2)
• Rear Red Clearance Lights (SAE Code: P3 or PC2)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

Middle Rear Trailer Light Requirements

• Red Clearance (Identification) Lights (SAE Code: P3)

Note: These should be mounted as high as practicable. The identification lights are typically mounted on the cross bar which goes below the boat. 

The SAE code is typically listed on your boat trailer lights.

For this particular boat trailer that is 80 inches wide or greater and less than 30 ft long, you can utilize the following lights and reflectors:

For the rear of the boat trailer, you can utilize one left rear trailer light that satisfies SAE Codes "S, I, A, T" and one right rear trailer light that satisfied SAE Codes "S, I, A, T". In the location your license plate is mounted, you will need a light to illuminate the license plate that satisfies SAE Code "L". On the center (rear) of the trailer, you will need clearance identification lights (a set of 3 red lights) that satisfy SAE Code "P3 or PC2".

You will also need 2 red side-facing reflectors and side marker lights, one will be mounted on each side near the rear of the boat trailer, facing sideways. The side-facing reflector must satisfy SAE Code "A" while the side marker light should abide by SAE Code "PC2". You can purchase lights and reflectors individually or a light that achieves both of these functions.

On the back of each fender, you will need to mount a red clearance light which abides by SAE code "P3 or PC2". 

For the front of the boat trailer, we recommend purchasing 4 amber reflector / side marker clearance combination lights and mounting them as shown in the above drawing. These lights should satisfy SAE Code "A" and "PC2". You can purchase lights and reflectors individually or a light that achieves both of these functions.

Notable Exception

• US regulations state that if your trailer is a boat trailer, you can use dual-face lights that are yellow on one side (facing forwards) and red on the other side (facing backwards) for front and rear clearance lights. This type of light is mounted on the trailer’s fender.

• Boat trailers greater than 10,000 lbs GVWR require an additional 2 pairs of rear upper body markings (reflective tape), 1 continuous bumper bar marking (reflective tape), 1 continuous rear lower body marking (reflective tape), and 2 continuous side markings (reflective tape).

Less than 80" Wide, Greater than 30 ft Long

Boat trailers that are greater than 30 ft long, yet less than 80 inches wide are among the least common boat trailers. There aren't many factory made boats that have these trailers, most of them are custom made. A boat that requires a trailer that is over 30 ft is typically wider than 80 inches. That being said, here are some of the lighting and reflector requirements you must abide by if your boat trailer meets these dimensions. 

For boat trailers less than 80 inches in width and greater than 30 ft in length, you are legally required to have the following lighting and reflectors:

Left Front Trailer Light Requirements

• Front Amber Reflector (SAE Code: A)
• Front Amber Clearance Lights (SAE Code: P2, PC, P3, or PC2)
• Front Amber Side Marker Lights (SAE Code: PC or PC2)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

Right Front Trailer Light Requirements

• Front Amber Reflector (SAE Code: A)
• Front Amber Clearance Lights (SAE Code: P2, PC, P3, or PC2)
• Front Amber Side Marker Lights (SAE Code: PC or PC2)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

Left Rear Trailer Light Requirements

• Red Stop / Turn Signal Lamp (SAE Code: S and I)
• Rear Red Reflector, Facing Side (SAE Code: A)
• Rear Red Reflector, Facing Rear (SAE Code: A)
• Red Tail (Running) Lights (SAE Code: T)
• Rear Red Side Marker Lights (SAE Code: PC or PC2)
• Rear Red Clearance Lights (SAE Code: P2, PC, P3, or PC2)
• License Plate Light (SAE Code: L)

Note: These are all required to be mounted a minimum of 15 inches above the ground, except the license plate light. The license plate light does not have a required height.

Right Rear Trailer Light Requirements

• Red Stop / Turn Signal Lamp (SAE Code: S and I)
• Rear Red Reflector, Facing Side (SAE Code: A)
• Rear Red Reflector, Facing Rear (SAE Code: A)
• Red Tail (Running) Lights (SAE Code: T)
• Rear Red Side Marker Lights (SAE Code: PC or PC2)
• Rear Red Clearance Lights (SAE Code: P2, PC, P3, or PC2)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

The SAE code is typically listed on your boat trailer lights or on their marketing material.

For this particular boat trailer that is less than 80 inches wide and greater than 30 ft long, you can utilize the following lights and reflectors:

For the rear of the boat trailer, you can utilize one left rear trailer light that satisfies SAE Codes "S, I, A, T" and one right rear trailer light that satisfied SAE Codes "S, I, A, T". In the location your license plate is mounted, you will need a light to illuminate the license plate that satisfies SAE Code "L".

You will also need 2 red side-facing reflectors and side marker lights, one will be mounted on each side near the rear of the boat trailer, facing sideways. The side-facing reflector must satisfy SAE Code "A" while the side marker light must satisfy SAE code "PC or PC2". You can purchase a combination light and reflector that achieves both of these requirements.

You will also need a red clearance light on the back of the fender on each side of the trailer, typically mounted on the back of the fender. The red clearance light should abide by SAE Code "P2, PC, P3, or PC2".

For the front of the boat trailer, we recommend purchasing 6x amber reflector and side marker clearance combination lights and mounting them as shown in the above drawing. The amber clearance lights will mount on the front of each fender, the front amber reflector and side marker light will mount at the front of the trailer on each side while the other side of reflector and side marker lights will mount at the midway point on the boat trailer. These lights should satisfy SAE Code "A" and "PC2".

You can use P2 or P3 lights as clearance lights, but they do not broadcast a wide enough angle flood to be used as side marker lights. However, you can use a PC2 rated light either way - so we recommend just buying all PC2 rated lights to keep it simple and avoid confusion. 

Notable Exception

• US regulations state that if your trailer is a boat trailer, you can use dual-face lights that are yellow on one side (facing forwards) and red on the other side (facing backwards) for front and rear clearance lights. This type of light is mounted on the trailer’s fender.

• Boat trailers greater than 10,000 lbs GVWR require an additional 2 pairs of rear upper body markings (reflective tape), 1 continuous bumper bar marking (reflective tape), 1 continuous rear lower body marking (reflective tape), and 2 continuous side markings (reflective tape). 

80" Wide or Greater, Greater than 30 ft Long

Boat trailers that are 80 inches wide or greater and greater than 30 ft long are most common among offshore boats. 

For boat trailers 80 inches in width or greater and greater than 30 ft in length, you are legally required to have the following trailer lighting and reflectors:

Left Front Trailer Light Requirements

• Front Amber Reflector (SAE Code: A)
• Front Amber Clearance Lights (SAE Code: P3 or PC2)
• Front Amber Side Marker Lights (SAE Code: PC2)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

Right Front Trailer Light Requirements

• Front Amber Reflector (SAE Code: A)
• Front Amber Clearance Lights (SAE Code: P3 or PC2)
• Front Amber Side Marker Lights (SAE Code: PC2)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

Left Rear Trailer Light Requirements

• Red Stop / Turn Signal Lamp (SAE Code: S and I)
• Rear Red Reflector, Facing Side (SAE Code: A)
• Rear Red Reflector, Facing Rear (SAE Code: A)
• Red Tail (Running) Lights (SAE Code: T)
• Rear Red Side Marker Lights (SAE Code: PC2)
• License Plate Light (SAE Code: L)

Note: These are all required to be mounted a minimum of 15 inches above the ground, except the license plate light. The license plate light does not have a required height.

Right Rear Trailer Light Requirements

• Red Stop / Turn Signal Lamp (SAE Code: S and I)
• Rear Red Reflector, Facing Side (SAE Code: A)
• Rear Red Reflector, Facing Rear (SAE Code: A)
• Red Tail (Running) Lights (SAE Code: T)
• Rear Red Side Marker Lights (SAE Code: PC2)

Note: These are all required to be mounted a minimum of 15 inches above the ground.

Middle Rear Trailer Light Requirements

• Red Clearance (Identification) Lights (SAE Code: P3)

Note: These should be mounted as high as practicable. The identification lights are typically mounted on the cross bar which goes below the boat. 

The SAE code is typically listed on your boat trailer lights or on their marketing material.

For this particular boat trailer that is greater than 80 inches wide and greater than 30 ft long, you can utilize the following lights and reflectors:

For the rear of the boat trailer, you can utilize one left rear trailer light that satisfies SAE Codes "S, I, A, T" and one right rear trailer light that satisfied SAE Codes "S, I, A, T". In the location your license plate is mounted, you will need a light to illuminate the license plate that satisfies SAE Code "L".

You will also need 2 red side-facing reflectors and side marker lights, one will be mounted on each side near the rear of the boat trailer, facing sideways. The side-facing reflector must satisfy SAE Code "A" while the side marker light must abide by SAE Code "PC2". You can purchase side marker, reflector combination light as well to put these two requirements into one fixture. 

On the rear of each fender, you will need to mount a red clearance light which satisfies SAE Code "P3" or "PC2". 

For the front of the boat trailer, we recommend purchasing 6x amber reflector and side marker clearance combination lights and mounting them as shown in the above drawing. These lights will satisfy SAE Code "A" and "PC2". You can use P3 lights as clearance lights, but they do not broadcast a wide enough angle flood to be used as side marker lights. However, you can use a PC2 rated light for both clearance or side marker lights - so we recommend just buying all PC2 rated lights.

Notable Exception

• US regulations state that if your trailer is a boat trailer, you can use dual-face lights that are yellow on one side (facing forwards) and red on the other side (facing backwards) for front and rear clearance lights. This type of light is mounted on the trailer’s fender.

• Boat trailers greater than 10,000 lbs GVWR require an additional 2 pairs of rear upper body markings (reflective tape), 1 continuous bumper bar marking (reflective tape), 1 continuous rear lower body marking (reflective tape), and 2 continuous side markings (reflective tape).

SAE Lighting Identification Codes for Boat Trailer Lights

Here is a list of the applicable SAE lighting identification codes for boat trailers. SAE stands for the Society of Automotive Engineers. Each code corresponds with the function that is required for each light or reflector. 

 

What is the difference between P2, PC, P3, or PC2 for side marker and clearance trailer lights?

P2 & P3 trailer lights can be mounted at the front or the rear of the boat trailer. They broadcast a 45 degree angle of illumination from the centerline of the light, for a total of 90 degrees of coverage. These lights can be seen well when facing them directly, but they cannot be seen as well when mounted on the side of the trailer because they do not flood as much. These lights must be mounted square on the front, back, or side of the trailer. 

The difference in P2 and P3 is the P3 rating is for trailers that are 80 inches wide or wider.

The "PC" literally stands for photometrically certified. In actuality, this means the lights broadcast a wider flood angle. PC & PC2 trailer lights provide a 90 degree angle of illumination from the centerline of the light, for a total of 180 degrees of coverage. This wide angle illumination allows these trailer lights to not only be used as a clearance light, but also be used as a side marker light.

The difference in PC and PC2 SAE rating is the PC2 rating is for trailers that are 80 inches wide or wider.

To put it simple, a PC or PC2 rated light can be used for the same applications as a P2 or P3 rated light, but a P2 or P3 rated light cannot always be used as a PC or PC2 rated light. A PC2 rated light is recommended as it fulfills the constraints of the other ratings (P2, P3, and PC).  

In terms of side marker and clearance lights, a PC2 rated light can be used as both a side marker and clearance light for any trailer width. None of the other ratings (P2, P3, or PC) can meet this criteria.