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.
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