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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
Our Price: $35.90
Trailer Lights
Shipping Weight: 2 lbs
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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. Great 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 or call 1-800-940-8924 for expert service.
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  • Reviews (58)
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Peterson Trailer Lights - M540

  • Tail Lights
  • Kit
  • Incandescent Light
  • Red
  • 4-3/4L x 4-1/2W Inch
  • Surface Mount
  • Rear Reflector
  • Side Marker
  • Side Reflector
  • Stop/Turn/Tail
  • 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

Customer Satisfaction Score:

Customer Reviews

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

Average Customer Rating:  4.7 out of 5 stars   (58 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.


Peterson products are good quality Hopefully the bulbs survived the shipping Everything was rattling loosely around with no bubble wrap or Styrofoam peanuts and all the fragile signs on the box were covered up by the various shipping labels. I prefer to support the the independent sellers like etrailer but next time I’ll go with Amazon


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.


Actually I added an extra ground wire to each light. Worked great


Easy installation


Good product. Did not include instructions, but found the wiring diagram on website. Also, would be nice if the 4 pin adapter had a cover, but I used one from another setup I had. I mainly used old wiring in trailer that I was replacing to pull the new wiring on, through the small wiring tunnels. Everything tested well and I was able to use the trailer the same night I finished install.


It would have helped if an instruction sheet was included. Tested before install while hooked up to my truck. Needed to ground lights to get them to work and an instruction sheet would have eliminated much frustration. Wire connections on the lights also leaves room for improvement.

Etrailer Expert

Sierra K.


Yes, the white wire is for grounding. This kit does not have an instruction sheet but we do have this wiring help article explaining which colors do what:


We Mfg trailers only kit we use about 100 peer year


Always good products when shopping e-trailer. This light package was no different. Excellent service excellent product and excellent follow-up to make sure you're happy..

Sure would love if they would send me a hat and a 2X t-shirt to advertise for them lol. Seriously though buy it you won't regret it.


License Plate plastic lasted 2 hours.


Great wiring kit. Has everything you need to completely wire a new trailer.


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.


Replaced lights and wiring on 20 year old utility trailer. Easy install, good instructions. Trailer lives outside in all New England weather. Still working great after a year.


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.


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


Great price for the trailer lights also works well


best place to buy all your trailer needs


looks good, this my first Peterson light kit


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


Fast delivery. Product looks as display ed.


We are a mfg they are awesome to work w ith


great work


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.


exact replacement


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


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

Show More Reviews

See what our Experts say about this Peterson Trailer Lights

  • 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...
  • Can LED Trailer Tail Lights be Used With Original Wiring on Older Boat Trailer
    You can use the Peterson Light Kit # V944 on your boat trailer from 1982 with its original wiring. Just make sure that the wires are in good shape and not stripped or otherwise damaged/exposed and these LEDs will work.
    view full answer...
  • 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...
  • Availability of Replacement Tail Lights for Peterson Boat Trailer?
    The lights I recommend for you are the Peterson # M540. These are epoxy-sealed submersible lights which will stop water from interfering with the bulbs. Keep in mind this does not protect the wiring, so you may want to take a look at some liquid electrical tape, # SWC50122. I also recommend you use heat shrink such as # DW05450 for all your wiring, which will help protect it.
    view full answer...
  • 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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  • 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 trailers...
    view full answer...
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  • 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...
  • Parts Needed to Add Separate License Plate Bracket and Light With Peterson Light Kit M540
    You can tap into the running lights(brown wire) on the Peterson Light Kit # M540 with a Tap # SWC502905-1. That will allow you to run 16 Gauge Wire # 16-1-1 to a Optronics LED Trailer License Plate Light # OPT97FR. You will be able to ground the negative wire to the steel frame, as your light kit uses the frame for the ground circuits.
    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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