LED clearance lights are the small marker lights mounted on the corners and sides of trailers to show their width and position at night

Clearance lights serve a safety function: they tell other drivers where your trailer's edges are in low light or darkness. They're required by federal law on trailers wider than 80 inches or longer than 30 feet. Most trailers have them mounted on the front corners, rear corners, and sometimes along the sides. The lights are typically amber on the front and sides, and red on the rear.

LED clearance lights have largely replaced older incandescent bulbs because they draw less power from your trailer's electrical system, last much longer, and produce a brighter, more consistent light. If your trailer's clearance lights aren't working or you're replacing old ones, understanding the basics helps you choose the right replacement and know what to expect during installation.

Key Takeaways

  • Federal law requires clearance lights on trailers wider than 80 inches or longer than 30 feet, with amber lights on front and sides and red on the rear.
  • LED clearance lights draw less power than incandescent bulbs and last significantly longer, making them a practical upgrade for most trailers.
  • Clearance lights connect to your trailer's 12-volt electrical system and are wired in parallel, so each light operates independently if one fails.
  • Installation typically involves mounting the light housing to the trailer frame, running wire through conduit, and connecting to the trailer's main harness.
  • LED lights may require a load equalizer if your trailer's brake controller or flasher relay is designed for incandescent bulbs.

How clearance lights connect to your trailer's electrical system

Clearance lights run on your trailer's 12-volt system, the same circuit that powers your brake lights and turn signals. They draw power directly from the main connector that links your trailer to the tow vehicle. Most trailers use a standard 7-pin or 6-pin connector; the clearance lights typically tap into the running light wire (usually brown or yellow) that stays on whenever the tow vehicle's headlights are on.

The lights are wired in parallel, meaning each one has its own direct path to power and ground. This design ensures that if one light burns out or fails, the others continue working. The ground connection usually runs to a bare metal point on the trailer frame, completing the circuit. Because LED lights draw so little current compared to incandescent bulbs, they rarely overload the system, though very old trailers with corroded wiring may need a ground wire upgrade.

The difference between LED and incandescent clearance lights

Incandescent clearance lights use a heated filament to produce light, much like a household light bulb. They draw more power, generate heat, and typically burn out after 500 to 1,000 hours of use. LED lights produce light through a semiconductor and draw about 80 percent less power. They last 25,000 to 50,000 hours or more, meaning many trailers will never need to replace an LED clearance light.

The brightness difference is noticeable. LED lights produce a sharper, more uniform glow that's visible from farther away, especially in fog or rain. They also respond when ready to power, whereas incandescent bulbs take a fraction of a second to reach full brightness. The trade-off is cost: LED clearance lights typically run $15 to $40 per light, compared to $3 to $8 for incandescent bulbs. Over the life of the trailer, the LED investment pays for itself through fewer replacements and lower power draw.

When you need a load equalizer for LED lights

Some trailers have a brake controller or flasher relay designed to work with incandescent bulbs. These devices monitor the electrical load (how much power the lights draw) to detect burned-out bulbs. When you switch to LED lights, the load drops so dramatically that the controller may think a bulb has failed and trigger a warning light or disable the circuit.

A load equalizer is a small device that mimics the electrical load of an incandescent bulb, fooling the controller into thinking the old bulbs are still there. You install it in parallel with each LED light that's causing the problem. Not every trailer needs one—newer trailers with modern controllers often work fine with LEDs—but if your brake warning light comes on after switching to LEDs, a load equalizer solves it. They cost $10 to $25 each and take about five minutes to install.

Mounting clearance lights on your trailer

Clearance lights mount to the trailer frame using brackets and bolts, typically at the four corners (front and rear) and sometimes along the sides on longer trailers. The housing sits flush against the frame or fender, with the lens facing outward. Most lights come with a rubber gasket to seal the connection and prevent water from entering the housing.

To mount a light, drill or use existing holes in the trailer frame, slide the gasket over the mounting studs, and bolt the housing in place. Use stainless steel or galvanized bolts to resist corrosion. The wiring runs through conduit (plastic or metal tubing) along the trailer frame to protect it from abrasion and weather. The conduit typically connects to the main trailer harness near the coupler or tongue, where it ties into the running light circuit. If you're replacing existing lights, the conduit and wiring are usually already in place; you straightforward disconnect the old light and connect the new one.

Troubleshooting clearance lights that don't work

If one or more clearance lights aren't working, start by checking the bulb or LED element itself. Remove the lens (usually held by screws or a twist-lock ring) and look for a burned-out filament or a loose connection. If the bulb looks fine, the problem is likely in the wiring. Check that the main trailer connector is clean and fully seated in the tow vehicle's receiver. Corrosion on the connector pins is a common cause of electrical failure.

Next, trace the wire from the light back to the main harness and look for cuts, pinches, or loose connections. If the wire is damaged, it may need to be spliced and sealed with waterproof connectors. Test the ground connection by checking that the bare wire or bolt connecting to the frame is tight and free of rust. If multiple lights on the same side of the trailer are out, the problem is usually in the main harness or ground rather than in individual lights. A multimeter can confirm whether power is reaching the light housing; if power is present but the light doesn't work, the bulb or LED element has failed and needs replacement.

Choosing the right LED clearance light for your trailer

LED clearance lights come in different sizes and styles. The most common are 2-inch round or rectangular lights, though some trailers use 1-inch or 3-inch versions. Check your trailer's existing light housings to match the size, or measure the mounting holes if you're installing new ones. The lens color matters: amber for front and side lights, red for rear lights. Some lights have a clear lens with an amber or red LED inside; others have a colored lens with a white LED. Both work equally well.

Look for lights rated for 12-volt DC operation and designed for trailer use. They should have a sealed housing to keep water out and a gasket to prevent leaks. Many LED clearance lights are sold as direct replacements for specific trailer brands or models, which simplifies installation. If you're buying generic lights, verify that the mounting holes and connector type match your trailer. Most lights come with either a pigtail connector (a short wire with a connector on the end) or bare wires that you'll splice into the existing harness.

Frequently Asked Questions

Do I need clearance lights on a small utility trailer?

Federal law requires clearance lights on trailers wider than 80 inches or longer than 30 feet. Most small utility trailers fall below both thresholds and don't legally need them. However, adding them improves visibility and safety, especially on longer trips or in poor light. Many owners choose to install them anyway for peace of mind.

Can I use white LED lights instead of amber or red?

No. Federal regulations specify amber for front and side clearance lights and red for rear lights. White lights are not permitted for clearance markers. Using the wrong color can result in a citation and may void your trailer's registration in some states.

How do I know if my trailer's electrical system can handle LED lights?

LED lights draw so little power that they work on virtually any trailer's 12-volt system. The only exception is if your trailer has extremely corroded wiring or a damaged ground connection, which would prevent any light from working. If your incandescent lights worked fine, LEDs will work fine too.

What's the difference between a clearance light and a marker light?

Clearance lights and marker lights are often used interchangeably, but technically clearance lights show the width and length of the trailer, while marker lights are smaller lights that mark specific points. On most trailers, the corner lights serve both functions. The terms are used differently by different manufacturers, so check your trailer's documentation if you need to be precise.

Can I install LED clearance lights myself, or do I need a mechanic?

If you're comfortable with basic wiring and bolting things to a frame, you can install them yourself. The work involves mounting the light housing, running wire through conduit, and splicing into the existing harness. If you're unsure about any step, a trailer shop can handle it for $50 to $150 per light, including parts and labor.