bing tracking image
  1. Trailer Lights
  2. Optronics
  3. Clearance Lights
  4. Oval
  5. Incandescent Light
  6. Amber
Optronics Dual Bulb Trailer Clearance and Side Marker Light - Incandescent - Oval - Amber Lens
Optronics

Optronics Dual Bulb Trailer Clearance and Side Marker Light - Incandescent - Oval - Amber Lens

Part Number: MC66AB
In Stock
$4.03
Retail:$10.96
You Save: 63%
Trailer Lights
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.
By submitting this form, you understand and agree to our Terms of Sale, Website Terms of Use and Privacy Policy.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

4" x 2-1/16". Incandescent trailer light functions as a clearance and side marker light when properly mounted. Dual bulb design increases light output. Snap-on lens. Surface mount to trailer - hardware not included. PC rated. (2) 194 bulbs. Great Prices for the best trailer lights from Optronics. Optronics Dual Bulb Trailer Clearance and Side Marker Light - Incandescent - Oval - Amber Lens part number MC66AB can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
  • All Info
  • Reviews (107)
  • Q & A (0)
  • Photos

Optronics Trailer Lights - MC66AB

Highlights

  • Brighter Visibility: Dual 194 bulbs boost light output for easier trailer spotting at night.
  • One Light, Two Functions: Works as both a clearance and side marker light when mounted correctly.
  • Simple 12V Hookup: 2-wire design includes power lead and ground for easy trailer wiring.
  • Durable Build: Amber snap-on lens and ABS housing handle regular road use.
  • Road Legal: PC-rated and DOT compliant for safe, visible operation on the road.
  • Quick Surface Mount: 4" x 2-1/16" oval light installs on flat surfaces—hardware not included.

Features to know about

Brighter and Wider Coverage: Dual Bulb Incandescent Light

When you need a marker or clearance light that stands out clearly from the front and side, this dual bulb design delivers. At 4" long by 2-1/16" tall, the two 194 bulbs work together to increase light output so it’s easier for others to see your trailer in low-light conditions. It’s PC rated too, meaning it throws light 90 degrees to either side for a full 180-degree spread—bright and visible whether you’re looking straight on or from the side.

Reliable and Simple Power Setup: 2-Wire Design

No need to overthink wiring. This light uses a straightforward 2-wire setup—one power lead and one ground wire—so you can easily connect it to your trailer’s electrical system. If your old setup used the mounting hardware as a ground, just run the white wire back to that same point and you’re good to go. It’s made for a 12V DC system and pulls only 0.2 amps at 12.8V, keeping things efficient while staying bright.

Quick Replacement Without Guesswork: Direct Surface Mount

Swapping out worn lights shouldn’t be complicated. This one mounts directly to your trailer surface using the same standard spacing—3" center-to-center between holes—so most replacements line up cleanly without drilling new holes. The snap-on amber lens makes bulb swaps simple, and the ABS housing stands up to regular use without worrying about cracks or fading.

Built for Everyday Use: Durable but Non-Submersible

This light is ready for everyday towing, but it’s not designed for underwater use. The non-submersible construction works great for land trailers or general utility setups where moisture exposure is limited. For anything that regularly goes underwater, you’ll want a sealed version instead, but for daily towing and road use this one stays solid and dependable.

Exact Replacements You Can Trust: Cross-Compatible Design

If you’re matching an existing setup, this unit directly replaces several common models including Uni Bond # ML2043A, Truck Lite # 26301Y, Grote # 45263, Peterson # 135A, and Bargman # 30-58-002. That means less time figuring out fitment and more time getting back on the road with lights that look and perform like they should.

Specs

Dimensions

  • Overall dimensions: 4" long x 2-1/16" tall x 1-1/16" thick
  • Distance between mounting holes (center on center): 3"

Dimensional diagram of Optronics MC66AB dual bulb amber trailer clearance and side marker light showing length, height, thickness, and mounting hole spacing

Electrical

  • Bulb type: 194
  • Number of bulbs: 2
  • Power draw at 12.8V: 0.2 amps
  • System compatibility: 12V DC

Warranty

  • Warranty: 3-Year warranty

Diagram illustrating 180-degree light spread of a PC-rated trailer marker light showing 90-degree coverage to each side of centerline

  • PC-rated light coverage: 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.

MC66AB Optronics Dual Bulb Trailer Clearance and Side Marker Light - Incandescent - Oval - Amber Lens - PC Rated

Alternate part number: MC-66AB





Customer Satisfaction Score:

Ratings & Reviews

4.8

107 reviews
Review sort icon
4" x 2-1/16". Incandescent trailer light functions as a clearance and side marker light when properly mounted. Dual bulb design increases light output. Snap-on lens. Surface mount to trailer - hardware not included. PC rated. (2) 194 bulbs.

by:

The product was exactly what I wanted. The order shipped on time and the customer service was great.



by:

Fast shipping Great price



by:

fast shipping and work great



by:

Excellent service. Received items earlier than expected. Good packaging. Nothing damaged. Overall great customer service and a pleasure doing business with this vendor. Will definately use this company again.



by:

Price great! Lights arrived promptly! Installation easy and they work great!



by:

Great service and super fast shipping !



by:

Fast shipping. Installed but not tested.



by:

The light fit properly, was easy to wire, and lit up as it was supposed to.



by:

Great product & fast shipping. Will replace old ones perfectly. Happy with purchase



by:

The service is always GREAT. The prices are the best that I have found anywhere. They do a great job. The products are always just what i wanted. Keep up the wonderful service etrailer



by:

Though this is a more modern version of the marker lights that were on my 1995 Sundowner Sunlite 3-horse slant, the holes matched up perfectly for easy installation!



by:

Good quality light, just wish the wire pigtails were about 2" longer.



by:

Good quality replacement products

Doug S. profile picture

Doug S.

9/21/2016

Still working as it should



by:

like all other trailer lights, failed prior to one year.



by:

The light is an exact replacement part. The delivery time was as expected. The web site was easy to navigate and provide excellent information regarding the wiring on the trailer.



by:

Instant response following the order confirming they received it, followed up with shipping info and tracking when shipped and received it ahead of scheduled delivery! Will only use etrailer for my trailer needs.

Thanks



by:

This was a replacement for an RV Clearance light. Installed quick and works great. Thanks for the great service.



by:

Installation went great! I am the most satisfied with how quick the shipping was and customer service was the best! I will be using these guys for all my trailer part needs



by:

Great replacement for my old weathered lights. cheaper to buy new lights then just the lenses.. Yes these lights come with two bulbs installed.



by:

etrailer.com is an excellent online company! The products I received were exactly what I needed to fix up my old V-nose and get it back on the road. The shipping was lightning fast and excellent follow up communications. I would recommend etrailer.com to anyone, any time!! AAAAA+++++ company.



by:

I used just the lens cover. Was in a hurry when ordering but was pleased to find out that it fit as replacement on my camper trailer. Had great service from the staff at etrailer. Fast shipping, great communication and awesome site. Will definitely order from them again!



by:

After working on the old lights on my camper numerous times just prior to leaving on a trip and while traveling, I decided it was time to replace all of the lights. I purchased two new tail/brake lights, and four new side markers. The total price including shipping was just over $28 (I should have done this a long time ago). The lights arrived within 3 days of being ordered, and I was able to install them fairly quickly. I am so happy that I now have all six lights working perfectly, and shouldn't have to worry about them for a long time



by:

I bought these to replace the marker lights on my travel trailer. etrailer had the best price, and they looked to be good replacements. When I installed them they seemed to be as good or better than the lights than came with the trailer. After a year they seem to still look good and work just fine.



by:

There are weep holes on both sides, allowing water to get in regardless of which way they are mounted.

Mike L. profile picture
Etrailer Expert

Mike L.

8/1/2026

Hey Guy. The weep holes are present to allow any water that gets into the lamp housing to drain away.



by:

I've purchased from etrailer for years when I can't find things on Amazon. I no longer use Amazon so will be buying more from etrailer. Great company, great service, great videos.

Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

4/24/2025

I appreciate you picking us, Steve! You can always rely on us, we wont let you down.

Steve profile picture

Steve

4/24/2026

The light is still working.


25
25

See what our Experts say about this Optronics Trailer Lights

  • Replacement LED Red Clearance Light For A Bargman 58-Series Clearance Light
    Hey Luis, For an LED version of the Bargman 58 series clearance light you would want the LED Trailer Clearance or Side Marker Light w/ Reflex Reflector # MCL32RB. This is a surface mount design so you'll need to pick up some self-tapping screws and I'd also recommend using some butyl tape # AL28FJ on the backside of the mounting base to help prevent any water from leaking into the wall of the trailer.
    view full answer...
  • Recommended Replacement Light/Lens for an Older Reflect-O-Lite 400
    the Reflect-O-Lite 400 light has been discontinued for quite a while so there isn't going to be an exact replacement. Instead, the closest replacement lens we have is the Replacement Amber Lens for Optronics MC66 Series Clearance or Side Marker Trailer Light # A66AB or the Replacement Red Lens for Optronics MC66RB Clearance or SIde Marker Light # A66RB. Both of these lenses measure 4" long x 2" tall x 7/8" deep, and is made of acrylic. There's no guarantee it'll be compatible with your...
    view full answer...
  • 2013 Forest River 2300 Sunseeker Front Amber Running Light Replacement Lenses
    I don't have any way of knowing what light is on your 2014 Forest River 2300 Sunseeker. I can confirm that the Optronics Dual Bulb Trailer Clearance and Side Marker Light - Incandescent - Oval - Amber Lens # MC66AB is 4" long x 2-1/16" tall x 1-1/16" thick with base mounting holes 3 inches on center. It is an exact replacement for Uni Bond #ML2043A, Truck Lite #26301Y, Grote #45263, Peterson #135A, and Bargman #30-58-002. The lens replacement for this is Replacement Amber Lens for Optronics...
    view full answer...
  • Wiring Single Wire Clearance Lights on an Enclosed Trailer
    You will need to use a circuit tester, item # PTW2993 if needed, to test the wires exiting the trailer to figure out the wiring configuration with the trailer hooked up to the truck and the running lights on. You will probably find that you have taillight power on one of the green wires and no power on any of the other wires. In this case you would wire the two green wires to the power wire coming from the clearance light. You would then need to wire the two white wires coming from the...
    view full answer...
  • Clearance Trailer Lights With Replaceable Lens Recommendation
    We do have clearance lights that may work for you. The clearance lights we offer come in amber or red and we have either 1 or 2 bulb units. You mentioned you like the 2-bulb feature on some clearance lights. I recommend part # MC66RB. This light comes with 2 incandescent bulbs and has a red lens. The amber version of this light is part # MC66AB. Both of these lights use the replacement bulbs, part # A194B. These are push-in bulbs. The replacement lens for the red light assembly is part...
    view full answer...
    Image 1 for
  • Comparing Amber Clearance Lights with 1-Wire vs. 2 Wires
    The difference between a clearance light with one wire and one with two is simply that the 1-wire type uses the light's mounting hardware to establish the ground, rather than a separate ground wire. The two are interchangeable so long as the mounting surface on the trailer will allow you to drill a hole to let you attach the white ground wire to the frame. Alternately, you could attach the ground wire to another of the existing ground wires on the trailer.
    view full answer...
  • Replacement Amber Lens for Marker Light on a 32 Foot Yellowstone Camino Camper
    I wish we had a master list of the parts used on all trailers and RVs but we do not. So we have to go by measurements or part numbers on the individual parts if applicable. The amber version of lens A66RB is # A66AB. It is a replacement for light # MC66AB which is 4" long x 2-1/16" wide x 1-1/16" deep. And that light is a direct replacement for any of the lights below: Uni Bond ML2043A Truck Lite 26301Y Grote 45263 Peterson 135A Bargman 30-58-002
    view full answer...
  • Is railer Clearance and Side Marker Light, # MC66AB, Submersible
    The Trailer Clearance and Side Marker Light, # MC66AB, is not a submersible light. You will not want to put this light under water. A sealed light like # MCL49AB, would be the way to go. I have included a link to a video review of this light for you.
    view full answer...
  • Could Optronics Trailer Clearance Taillight # MC66AB Possibly Replace Lights that Hardware Ground
    The simple and efficient solution would be to go with the part # MC66AB that you mentioned and if you find that the lights ground through the hardware just run the white wire back to the mounting hardware and you'd be set.
    view full answer...
    Image 1 for
  • Replacement Lenses for Unknown Trailer Lamps
    We have a pretty large selection of replacement lenses available. I'd be happy to look at a photo of your current lenses if you'd care to send it along. You can simply attach the photo to a reply to this email. Also helpful would be any item or part numbers printed or stamped into the light fixture itself (not the lens). Any numbers on the lens itself would be DOT certifications, not a part number for the lens. Dimensions of your current lenses would be helpful as well. I've linked you...
    view full answer...


Info for this part was:

Employee Michael H
Expert Research:
Michael H
Employee Jameson C
Expert Research:
Jameson C
Employee Adam R
Expert Research:
Adam R
Employee Laura H
Updated by:
Laura H
Employee Brian T
Updated by:
Brian T
Employee Cole B
Installed by:
Cole B
Employee Randy B
Installed by:
Randy B
Employee Chris R
Video Edited:
Chris R
Employee Zach D
Video by:
Zach D

At etrailer we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time.


Product Experts Available Now!
Call 1-800-940-8924