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Peterson Light Kit for Trailers Under 80" Wide - 20' Harness - Driver and Passenger

Peterson Light Kit for Trailers Under 80" Wide - 20' Harness - Driver and Passenger

Item # M540
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M540 - Red Peterson Trailer Lights
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4-3/4" x 4-1/2" Square. Incandescent trailer light kit provides all legal lighting and reflectors for trailers under 80". Includes combination tail lights and side markers. Stud mount with included hardware. 20' Harness. PC rated. Lowest Prices for the best trailer lights from Peterson. Peterson Light Kit for Trailers Under 80" Wide - 20' Harness - Driver and Passenger part number M540 can be ordered online at etrailer.com or call 800-298-1624 for expert service.
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  • Reviews (25)
  • Q & A (5)
  • Videos (2)
  • Photos
  • Why etrailer?

Peterson Trailer Lights - M540

  • Tail Lights
  • Kit
  • Incandescent Light
  • Red
  • 4-1/2L x 4-1/2W Inch
  • Surface Mount
  • Stop/Turn/Tail
  • Side Marker
  • Side Reflector
  • Rear Reflector
  • Peterson

4-3/4" x 4-1/2" Square. Incandescent trailer light kit provides all legal lighting and reflectors for trailers under 80". Includes combination tail lights and side markers. Stud mount with included hardware. 20' Harness. PC rated.


  • Trailer light kit provides all legal lighting and reflectors for trailers under 80" wide
  • 2 Square combination tail lights provide 6 functions
    • Stop, tail, turn, side marker, side reflex, and rear reflex
    • Built-in license plate light on driver's-side light illuminates license plate
  • 2 Rectangular marker lights are included to provide rear clearance light function
    • Built-in reflex reflector removes the need for a separate reflector
  • Incandescent bulb can be easily replaced
  • Compatible with 12V DC systems
  • Mounts on surface of trailer with included studs
    • Includes license plate bracket for mounting driver's side light
  • 20' Wiring harness for making connections
  • DOT compliant
  • PC rated
  • Made in the USA


  • Tail lights:
    • Dimensions: 4-3/4" long x 4-1/2" tall x 2-13/16" deep
    • Distance between mounting studs (center on center): 2"
    • Power draw at 12V: 2.2 amps
    • Bulb type: 1157 and 168
  • Clearance lights:
    • Dimensions: 2-3/4" long x 2-1/8" tall x 1" deep
    • Power draw at 12V: 0.25 amps
    • Bulb type: 194
  • 1-Year limited warranty

Manufacturer Cross Reference

Light will work as an exact replacement for:

Wesbar # 7504

Optronics # TL27BK

Peterson M540 Trailer Light Kit Dimensions

PC-Rated Lights

Diagram of light spread for PC rated light

A PC-rated light produces a 90-degree angle of light to either side of its centerline for a total of 180 degrees of coverage. This beam pattern can be clearly seen when you are standing directly in front of the light, as well as when you are standing on either side of the light. When properly installed, this type of light can function as both a front clearance light and a side marker light or as a rear clearance light and side marker light.

M540 Peterson Square Combination Trailer Light Kit for Trailers Under 80" Wide - 20' Wire Harness - Incandescent - Stud Mount - Driver and Passenger Side

California residents: click here

Video of Peterson Light Kit for Trailers Under 80" Wide - 20' Harness - Driver and Passenger

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Review of Peterson Trailer Lights - Tail Lights - M540

Today we're gonna take a look at the Peterson light kit for trailers under 80 inches wide. This is going to have a 20-foot wiring harness and it's going to work for the driver and passenger side of our trailer. This is going to be a quick and easy kit to get your trailer up to code, if you want to have it be DOT compliant you'll need to have your two trailer marker lights, and also our two side marker lights. We'll also have our 20 feet of cable, or our 20 feet of wire, and a license plate bracket, as well as some hardware to get everything installed.Again, we'll have our two trailer lights that are gonna go on the rear. There's going to be our large lens and reflector there, as well as the light itself, and then two side reflectors. And on the driver's side, there's going to be a clear lens at the bottom that's going to help to illuminate our license plate, since our license plate is going to be mounted on the driver's side.We'll have our bracket that's going to be mounted right behind that, and then we can mount our license plate just below it and have that light illuminate our license plate.

So you can see on the back of our light, we'll have the two posts to mount up. On the back of our side marker light, there's just one post and one wire that we'll have to connect. So we'll have six nuts, locking nuts, that come with our kit to mount that up. And that light will stay there, there we go.We'll have six of these nuts, one for each of those posts, to get everything connected as it should be. We'll also have two quick-splice connections for connecting into our two side marker lights, and then some small clips that's going to help keep our wiring up and out of the way.

You just slide the wire in on one side, or slide it in the other way, and then you would slide the smaller end or the larger end onto a flat part of your trailer. So this works really well on trailers where you have slats that you can run that onto.And again, we're going to have our four-pole wiring. So we'll have our four-pole connector at the one end to hook into our vehicle. We'll have our ground post, which will be the white wire, and then we'll have our running light circuit which is going to go to the brown wire. Now we have two of these wires, one for either side.

That's for the running lights. You'll need a running light connection for both sides. Then we'll have our yellow, which is going to be for the driver's side turn and taillight, and the green wire which is going to be for the passenger side turn and taillight.We'll have our bare ends, white for ground. So you'll need to grab a ring terminal to get this connected to and either use an existing grounding point, or a self-tapping screw to ground that into a metal or chassis ground on your trailer. And then we'll have our two ends for either side.

The brown and yellow for our driver's side, and the green and brown for our passenger side.I'll just show you real quickly how to wire that up and what our light will look like whenever it's lit. The back will have some small connectors there. You're just gonna push the wire into the appropriate slot. So the brown, it's actually labeled. It says tail, in parentheses brown. It's gonna go into these two connections here. So you're just going to push your wire in. It's a good idea to twist the end of that wire to make it a little bit more resilient. I'm just gonna push that end in. That's gonna grab and hold onto that wire, so you don't have to worry about it coming out. If you do need to take it out or if you switch the wires around, there's a smaller hole at the back there, it's kind of hard to see. The smaller hole just beneath it, if you push something in on the end there, that will actually release the wire back out.I ended up using a zip tie or a cable tie to remove that. Just whittled it down a little bit. You can use a pen, whatever you got really. But as soon as you push that it'll let the wire come back out.The other wire I put in there, so this is our driver's side. It's gonna be our yellow, so that's gonna give us our stop and turn signals. And then we can use the post to act as the ground for the light. So I'll connect my ground to the light on that post back there, turn on our power. And you can see our light's gonna come on.So this is gonna be our running light signal, and then when our turn signal's on, so you can see that light is going to get brighter to indicate that we're turning. Go ahead and flip the lights out in the studio here so you can get a better idea of how bright that's going to be. Our light also comes through on the side. And we'll also have our light at the bottom, as you can see there.It's gonna be the same thing for our passenger side, just without that bottom lens for the license plate. And then for the trailer lights, or the clearance lights, it's gonna be similar. So again, to remove the wires from the back, just gonna push in on that little spot and it'll let me release those wires. So it's a really easy connection there, you don't have to worry about any butt 00:05:58 connectors for the taillights. For our other concoction here, we will have to wire in our running light circuit. And then again, we'll just use the post as our ground.So that's gonna be your running lights, or your clearance marker lights. Turn the lights out again in the studio so you can get an idea of how bright that's going to be. Again, it's going to make sure that we're DOT compliant for all states. So just giving you an idea of how bright everything's going to be and what it's going to look like whenever you have it all wired up and installed.As far as the dimensions for this, we are going to have . our taillights are going to be three . or 4 3/4 of an inch long, that's going to that outer reflector there, and then it's going to be 4 1/2 inches tall, and 2 13/16 of an inch deep. That's going from the back of the housing to the front of the light. Our studs coming off the back, it's gonna be about 7/8 of an inch.For our clearance lights, they're going to be 2 3/4 of an inch long by 2 1/8 tall, and about one inch deep. Flip my ruler around here so you can actually see. The distance between our posts on the back of our taillights is going to be two inches apart. This is going to take bulb type 1157. Our clearance lights are going to take bulb type 194, which is going to be a 12-volt bolt. You can find those bolts here at etrailer.com if you ever need to replace them.One last thing that I want to mention with these lights is that this product is made in the USA. And that's going to do it for our look at the Peterson light kit for trailers under 80 inches wide.

Customer Reviews

Peterson Light Kit for Trailers Under 80" Wide - 20' Harness - Driver and Passenger - M540

Average Customer Rating:  4.8 out of 5 stars   (25 Customer Reviews)

4-3/4" x 4-1/2" Square. Incandescent trailer light kit provides all legal lighting and reflectors for trailers under 80". Includes combination tail lights and side markers. Stud mount with included hardware. 20' Harness. PC rated.

- M540

First, I must say I've been very satisfied overall with etrailer and continue to be a return customer. The odering process is straightforward and etrailer kept me informed of the shipping status. I did have a minor problem with the light kit. After a quick phone call with etrailer, they were able to remedy the problem in a few minutes. I also find their installation videos and wiring diagrams to be very useful.

- M540

Shipping was quick and the lights worked out great! Very straight forward install.

- M540

Love my agent she was so friendly and professional, and the service was great, product was recorded fast and is also great

- M540

This arrived QUICK. Request for review was even quicker...I haven’t had time to install/test tires.

- M540

Very nice complete wiring set. Very fast delivery in 3 days with the standard ground shipping.

- M540

Rating says it all, 6 stars!

- M540

The only issue I have with this assembly is the quick connection at the taillights. It was nearly impossible to make the connection hold. Screw tabs would have been better.

- M540

All the items were quickly delivered and in great shape upon arrival. Only complaint is that there were no instructions for installation. That’s fine for people who know what they’re doing but I’m not that guy. A simple set of instructions would be helpful.

- M540

Great service.

- M540

looks good, this my first Peterson light kit

- M540

Much better than the cheap made in China ones that I have tried before. This set is very good quality, and a robust wire harness, unlike some of the newer Chinese versions I have purchased. I would expect to get about 5-10 years out of this set.

- M540

Great set of lights. An easy install other than my own issue with the ground.

- M540

exact replacement

- M540

Very nice, just what I ordered. It came a day early too!

- M540

The exact replacement for my trailer lights with everything needed. Highly recommend.

- M540

Everything worked as specified

- M540

Great price for the trailer lights also works well

- M540

Has everything I needed

- M540

Great product, fast shipping A++++++

- M540

works great. thanks

- M540

Shipped quickly and product exactly as described!

- M540

- M540

- M540

- M540



Ask the Experts about this Peterson Trailer Lights

  • Submersible Version of Peterson Light Kit part # M540
    For a submersible version of the Peterson Light Kit part # M540 that you referenced you'd want the # TL5RK which comes with the exact same style of lights, wiring and bracket but is designed for boat trailer applications like yours! I attached an install video for this for you to check out as well.
    view full answer...
  • Recommended Tail Lights and Clearance Lights For 5' x 8' Utility Trailer
    I would be happy to help! For replacement lights I recommend starting with the Peterson Light Kit for Trailers Under 80" Wide - 20' Harness - Driver and Passenger # M540 which includes the two tail lights, and two amber clearance lights. Since you mentioned that you also have red side marker lights on the front I recommend two of the # MC48RB. This will include all of the new wiring and lights needed, but I do recommend using heat shrink butt connectors like the # DW05744-10 to give...
    view full answer...
  • Will Peterson Light Kit #M540 Replace the Lights on my Trailer?
    You would be able to add lights with the Peterson Light Kit for Trailers # M540 and since they have a new 4 way connection it should solve any issue you're having; that being said, I can run you through some quick steps to troubleshoot the lights on the trailer and avoid having to buy a new set of lights. It sounds like there may be an issue with the wiring harness on the vehicle or the trailer wiring that is keeping these lights from functioning, so I'll give you a couple of troubleshooting...
    view full answer...
  • Will The Peterson M540 Light Kit Fit A Bracket With 2-1/4" of Head Room?
    I measured from the center of the mounting studs to the top of the lights that come with the Peterson Light Kit # M540 and it is 2-1/2". Just to make sure, I also measure the Optronics Under 80" Trailer Light Kit with 25' Wiring Harness # TL5RK the same way, and they measure exactly the same, unfortunately. With that said, I may have another option available, but the lights will be completely different. If you look at the Optronics Trailer Light Kit # TL16RK, which technically is for...
    view full answer...
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  • Recommended Trailer Wiring for 5x10 Trailer with 4-Way Trailer Connector
    If you have a 4-way trailer connector like # 118418 then I recommend using a wishbone harness to wire your trailer. The 20 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 30" Ground # A20WB is my recommendation for your wiring because it will allow you to run 2 wired to each side. You will run the brown and yellow to the driver's side, and the other brown and green wire to the passenger side. The white wire will get connected to the trailer frame as a ground. The brown wires on each...
    view full answer...
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Info for this part was:

Employee Jameson C
Expert Research:
Jameson C
Employee Joshua S
Video by:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Kathleen M
Installed by:
Kathleen M
Employee Ryan G
Installed by:
Ryan G
Employee Daron K
Edited by:
Daron K
Employee Brian T
Written by:
Brian T

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