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Identification Light Bar for Trailers over 80" Wide - Submersible - 3 Diodes - Red Lens

Identification Light Bar for Trailers over 80" Wide - Submersible - 3 Diodes - Red Lens

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Shipping Weight: 0.6 lbs
Optronics Clearance Lights - MCL78RB
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17" Long x 1-3/8" tall x 1" deep. Waterproof identification light bar is designed for trailers wider than 80". Durable polycarbonate lens and housing. Surface mount to trailer. 2-Wire pigtail. Lowest Prices for the best trailer lights from Optronics. Identification Light Bar for Trailers over 80" Wide - Submersible - 3 Diodes - Red Lens part number MCL78RB can be ordered online at etrailer.com or call 800-298-1624 for expert service.
  • All Info
  • Reviews (80)
  • Q & A (6)
  • Photos
  • Why etrailer?

Optronics Trailer Lights

  • Clearance Lights
  • ID Bar
  • LED Light
  • Red
  • 17L x 1-1/2W Inch
  • Surface Mount
  • Optronics
  • Rear Clearance
  • Submersible Lights

17" Long x 1-3/8" tall x 1" deep. Waterproof identification light bar is designed for trailers wider than 80". Durable polycarbonate lens and housing. Surface mount to trailer. 2-Wire pigtail.


  • LED Trailer light functions as an identification light bar for trailers wider than 80"
  • Sonically sealed, waterproof housing and lens unit is submersible
  • LEDs make great replacements for incandescent lights
    • Last 50 times longer
    • More efficient - provide brighter light with less power output
    • No bulbs to replace - no brittle filaments
  • Durable polycarbonate housing and lens
  • Red lens over white LEDs
  • Compatible with 12V DC systems
  • Mounts to surface of trailer - hardware not included
  • 2-Wire pigtail includes power lead and ground wire
  • P2 rated


  • Quantity: 1 identification light bar
  • Dimensions: 17" long x 1-3/8" tall x 1" thick
  • Distance between mounting holes (center on center): 16-1/8"
  • Diodes: 3
  • Power draw at 12.8V: 0.022 amps
  • Lifetime warranty on LEDs

Optronics MCL78 Series Identification Light Bar Dimensions

Sonically Sealed, Waterproof Trailer Light

The waterproof construction of this light makes it ideal for use on trailers that may be submerged, like a boat trailer. The housing and lens are sonically sealed together to create a single unit, which means that water will not get into the light and damage the diodes or circuit board.

P2-Rated Lights

Diagram of light spread for P2 rated light

A P2-rated light produces a 45-degree angle of light to either side of its centerline for a total of 90 degrees of coverage. This beam pattern can be seen straight on, but it cannot be seen clearly from the side. So this type of light can be used as either a side marker light or a clearance light, but it cannot function as both. If you need both functions, then you must install 2 separate lights on your trailer - one as a front or rear clearance light and one as a side marker light.

MCL78RB Optronics ID Light Bar for Trailers over 80" Wide - Submersible - 3 Diodes - Red Lens - P2 Rated

Alternate part number: MCL-78RB

Item # MCL78RB

California residents: click here

Customer Reviews

Identification Light Bar for Trailers over 80" Wide - Submersible - 3 Diodes - Red Lens - MCL78RB

Average Customer Rating:  4.8 out of 5 stars   (80 Customer Reviews)

17" Long x 1-3/8" tall x 1" deep. Waterproof identification light bar is designed for trailers wider than 80". Durable polycarbonate lens and housing. Surface mount to trailer. 2-Wire pigtail.


Light is just what I had anticipated. However, what I did not anticipate was the small hole size. And because the mounting hardware does not come with, I had to dig through my stash to fine two that worked. Seems like mounting hardware should be included, especially if hole size is so small with limited solutions.


Product quality appears excellent. I chose this one because it was LED, sealed, and because the spacing between the bolt holes matched the holes in my trailer from the old light housing. I had to enlarge the center hole a bit to allow the ground connector to pass through but that was easy enough with a stepped bit. I was able to remove the old light, clean up the metal frame and bolt this one right in place. I was about to drill another hole for the ground wire's ring terminal when I realized that it was long enough to connect to one of the bolts. That is probably obvious to many but I almost missed it. One minor complaint was that the holes for the mounting bolts were really small. I was able to find a pair of tiny bolts in my junk drawer that fit but they are REALLY small. I think this would be better if the holes were a bit larger.


Works perfectly!!!! Looks really good too, even though it is just a trailer. Great product & company to do business with

Kerry b - 08/21/2018


This light is an exact replacement of the original product on my trailer. The trailer manufacturer drilled and broke the water tight seal when the original was installed.


Awesome. Great replacement of the incandescent version and fit in existing holes!


Thanks for the great service as always! Before and after photos....

by: 02/11/2021


I guess it’s ok for a center clearance light. It’ll do the job, i suppose. Guess I didn’t see the part in the title where it said that it was only a 3 diode. I figured there’d be an LED behind each circle on the front of the light but there’s not. For over 20 bucks, you’d think there would be.


I bought this light one year ago and it is a major improvement over the old light I replaced. Easy to install and is bright.


Purchased one of these lights from Amazon and was junk. Found etrailer site and this light is the same as the OEM. Now hope some knucklehead won't hit my trailer in the parking lot again!!


Rebuilt a trailer. Everything I received from etrailer was quality. Trailer came out great. Thanks Etrailer.



Ordered new red & yellow led signal markers and a new lid for the trailer. All arrived in 3-4 days and all the old Lights’s swapped out easy. Trailer looks new!


Lights were the exact same ones on my trailer that I couldnt find anywhere else. Great site and love the personal follow up touch


This idenrifaction led light bar works perfectly and matched the original hole pattern of the light I waas replacing. I was concerned that it my not be bright enough since it only had one led per light but that was not the case. It is plenty bright and easily visible even in daylight.


Products were delivered faster than I expected...Will definitely order from etrailer in the future..Excellent service...


Side marker lights were perfect, however stop/tail lights did not fit the curve trailer frame insert.


Priced right .simple wiring...box was damaged seem light was too big for the box was hanging out.minor scratches wasn't worth sending back and waiting for a new one


I have placed 2 orders with etrailer. Both orders were for trailer lights. The videos explaining the operation of the lights were very helpful. Prices were very competitive and the shipping costs were reasonable. Both orders shipped the same day. I feel the folks at etrailer went out of there way to give me a pleasant experience.


The 3 LEDs is kind of lame considering the light housing appears to be made for 11 LEDs. It does work, and has worked for over a year. It is acceptable considering how inexpensive it is.


This is a perfect product, fit like the OEM on my Heritage Chaparral Trailer. Good quality and very fast shipping. Thanks again.


Great service as always. Will continue to use etrailer for all of my trailer needs. Light was as described and quality appeared good.


Great value and quality!

Bobby - 11/11/2018


Always great service. Pat C. did address all my concerns with this order. Great company to deal with. They have a great selection of products to choose from for most applications.


Great product. Easy install. Quick ship ping.

Show More Reviews

Ask the Experts about this Optronics Trailer Lights

  • How To Use the Identification Light Bar MCL78RB As a Third Brake Light
    Yes, the Identification Light Bar part # MCL78RB will work as a third brake light. However, you will likely need to separate the stop and turn signal circuit before you power the light or else it would flash with the turn signals as well. The Pacer Performance 3rd Brake Light Logic Module part # PP20-702 however will solve this problem. I have attached a wiring diagram of the module for you as well. The green wire on this module will go to the black wire on the light.
    view full answer...
    Image 1 for
  • Amber Light Bar About 16 Inches Long for Trailer Clearance Light
    We don't have an amber colored light that's exactly like the # MCL78RB you referenced. The closest I have is the Peterson Mini Identification Trailer Light Bar item # 427800, which measures 16-5/8" long and mounts on 16-1/8" centers. Note that this is also an incandescent light, not LED.
    view full answer...
  • Can Optronics Identification LED Light Bar MCL78RB be Used in Place of Peterson Light 150-3
    Yes! You can use LED light bar # MCL78RB in place of the Peterson 3-light ID light bar that you have now. I have included a link to a video review of this light bar for you.
    view full answer...
  • Matching Horse Trailer Clearance Lights and Light Bar
    I think that your selection of light bar # MCL78RB and clearance light # MCL66RB will look could together. Since the clearance lights get screwed onto a surface you shouldn't have a problem with them getting knocked off. I have linked videos on each of these lights for you.
    view full answer...
  • Recommended Trailer One Piece Identification Light for Trailers Over 80 Inches Wide
    If you need a three light LED bar like you are describing I recommend the # MCL78RB or the # MCL98RB. As for if the legality of the solid # STL69RRXB light bar, I totally agree with you it's not worth the ticket, that being said you will need to contact the Florida DOT, because I was not able to find any information regarding this on their website. I have linked our help article on trailer lighting and regulations as well as the clearance LED ID bars for your convenience.
    view full answer...
  • Replacement LED Light Recommendations For Trailer
    For a grommet mount red 2 inch clearance light I recommend part # MCL55R1224B. This light uses a 2-wire pigtail, part # A46PB for installation. If you need amber, you would order part # MCL55A1224B. Installed without a grommet, these lights measure 2 inches diameter x 1 inch deep. You can use the 2 inch grommet part # A54GB for this light for a flush mount. It would require a 2-5/16 inch mounting hole. The tail lights I recommend are the Optronics GLOLight LED Stop/Turn/Tail Light,...
    view full answer...

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Info for this part was:

Employee Michael H
Expert Research:
Michael H
Employee Jacob T
Video Edited:
Jacob T
Employee Laura H
Updated by:
Laura H
Employee Brian T
Updated by:
Brian T
Employee Cole B
Installed by:
Cole B
Employee Shane H
Test Fit:
Shane H
Employee Michael B
Video by:
Michael B

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