This square clearance and side marker light combines a PC-rating with a reflectorized amber lens, so it pulls double duty. When it’s mounted at a 45-degree angle, it functions as both a clearance and side marker light, keeping your trailer visible from multiple directions. Because the lens is already reflectorized, you don’t need a separate reflector to meet DOT requirements—everything’s built right in for a clean, compliant setup.
Installing this light is simple thanks to its single-wire setup and stud mount. The single lead wire handles power, while the light grounds through the mounting stud—no extra ground wire needed. It’s a quick, tidy connection that keeps wiring minimal and secure. The stud mount makes for a solid mechanical connection that holds up over time without extra brackets or adaptors.
Keeping things working is easy with this design. The lens screws down for secure sealing but can be removed when it’s time to replace the bulb or lens. That means you don’t have to toss the whole assembly if one part wears out—you can service what you need right on the spot.
At just 2-7/8" long, 2-1/8" wide, and 15/16" deep, this light stays low-profile while still producing bright amber illumination. Its rectangular shape blends easily with most trailer lighting layouts without sticking out or catching on anything. Whether you’re replacing an old incandescent unit or matching existing lights, it fits neatly and looks right at home.
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Today we have Optronics Square Trailer Clearance Light, part number MC37AB. This light features a reflectorized lens that is DOT compliant. Both the lens and the bulb are replaceable, to make sure this light will last. It is a single wire system, meaning the wire lead that we have will be for your power source and the mounting stud on the back will double as our electrical ground. Next, we will grab our power supply and test the light. We will take our ground connection and clip it to the stud and we will take our power source and clip it to our wire lead. Next we will turn off our overhead light, to show you how bright the light is. And there you have it, Optronics Square Trailer Clearance Light, part number MC37AB.
Ratings & Reviews
Fast delivery ,good price , a Great items " etrailer.com " nice company
Their products work great on our traile rs
The lights were of great quality and the perfect match for other lights on the trailer.
The side marker light arrived a day ahead of the promised date and exactly what I needed.
Great product, very slow shipping. It didn't move for days. Still worth it.
This is a great product it took me less than 10 minutes to install 2 of these lights, entrails customer service is second to none thank you etrailor
Extremely pleased with my order. It works great. My order even arrived two days early. Thanks etrailer.
Always a pleasure doing business with etrailer. Product is always accurate, on time and communication is great. Thank you for being an example of what customer service should be...there aren't many like you
Side marker lights were just what I wanted and were delivered in 3 working days. Thanks!
The product I bought was perfect for my trailer. The light fit and was easy to install.
etrailer is an excellent source.
The trailer lights were shipped and delivered in a reasonable time and the price paid was very good. I appreciate the timely communications that kept me updated on the status of the order.
Average quality by today's standards but price couldn't be beat.
I have an old trailer and this type of light seems to be very rare with the stud and wire so I was happy to find this replacement.
Purchased 2 of these that were exact replacements for lights that had been damaged or destroyed. Installed both in about 10 minutes with ease. Self grounding attachment stud was a real plus. Product was high quality and service was excellent. I have ordered several items in the past from etrailer and shipments were very fast and the people are great to work with.
Light was exact match to what on the trailer other then mounting bolt was slightly smaller but did not effect the install. Just took a few minutes to replace broken light.
Great looking tire. Bought a used trailer. Guy said tires were "new" but date code says they are not. Both had cracking & were made in 2010. These new tires were both made a month or so ago from ordering. Practically direct from factory they are so new. Look good and bolted right on. No issues. Much more confident that I've reduced the chance of a blow out.
Exactly what I ordered, easy installation, works perfectly . . . will definitely purchase from here again the next time I need to replace one of my trailer lights.
The side marker lights work great! The folks at etrailer.com are top notch, super nice and really helpful. Nothing but good things to say about the people and the service.
exactly what I needed and fast delivery
Trailer Side Marker Lights received fully met my expectations.
Ordering process was streamlined through the eTrailer.com website.
Response time on order and shipping was outstanding.
eTrailer is a great company for the consumer!!!
I just recently got the optronix trailer lights and marker lights installed on my trailer,and they work perfect. I will definitely buy from etrailer again.Thanks for having reliable products!
Perfect match for the lights on my Top Hat trailer. Quick install and now it’s like new
Service was excellent but I cannot review the items due to a wiring harness issue.
Your company displays all the aspects of an excellent customer focus business.
I felt like a preferred customer een though I ordered a couple marker lights. Delivery was quick, follow up was quick and item info well defined.
Thank you!
Rebuilt my Big Tex trailer, etrailer had the exact match of the original clearance lights. Looks just like new.
This side marker light was an exact replacement for a busted light on my boat trailer.
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