If you’re towing a trailer—whether it’s for work, play, or something in between—making sure your trailer lights are up to code isn’t just smart, it’s the law. At JL Mobile Truck & Trailer Repair, we field questions all the time about trailer lighting: When are lights required? What should I do if my trailer lights stop working? And now, with our new towing services and fully equipped shop building, we offer solutions whether you need a quick fix or major repairs.
When Are Trailer Lights Required?
The short answer: any time your trailer is used on public roads, and especially:
- Between sunset and sunrise
- During low-visibility conditions (fog, heavy rain, or snow)
- When your trailer blocks the taillights or signals of your tow vehicle
Federal and state law require trailers to have functional lights when on the road. This means your trailer MUST have:
- Stop (brake) lights
- Tail lights
- Turn signals
- Rear reflectors
If your trailer is over certain widths (usually 80 inches or wider) or lengths (30 feet or longer), or is over a certain weight, additional lighting and reflectors are often required—check your local regulations for specifics.
Basic Lighting Requirements by Size
- Most trailers need: Two tail lights, two brake lights, two turn signals, a license plate light, rear reflectors, and side marker lights.
- Small trailers (<6 ft long): May only need one tail light, one brake light, and one rear reflector.
- Wider/longer trailers: Require additional side marker and clearance lights.
Common Reasons for Trailer Lights Not Working
Flickering or dead trailer lights can turn a simple haul into a roadside headache. Here are the most frequent causes and solutions:
- Bad Ground Connection: The most common culprit. Check that the trailer’s ground wire (usually white) is securely connected to the trailer frame. Clean off any rust or corrosion for a solid connection.
- Dirty/Corroded Connectors: Plugs can get dirty or corroded, causing intermittent or dead lights. Clean them well and check for damage.
- Defective Bulbs: Swap in a new bulb if a single light is out; if it’s all the lights, the issue is likely wiring or the tow vehicle.
- Wiring Issues: Damaged, pinched, or chafed wires can break connections. Inspect for cuts and replace as needed.
- Tow Vehicle Fuse Blown: Check your tow vehicle’s fuse box if none of the trailer lights work at all.
- Compatibility Issues: Especially with newer vehicles and LED trailer lights; sometimes additional adapters or resistors are needed.
How JL Mobile Truck & Trailer Repair Can Help
JL Mobile is more than just your go-to mobile mechanic. Our shop building in Joplin is fully equipped for all trailer electrical repairs, rewiring, and light installations. Our seasoned team makes short work of trailer troubleshooting, so you’re back on the road quickly and safely. Plus, with our new towing services, if your trailer—or the vehicle towing it—can’t make it to our shop, we’ll tow it for you!
We also offer:
- Hydraulic system repair
- Diesel engine repair
- Engine swaps and rebuilds
- Fleet maintenance
- Transmission repairs
- Oil changes and more
Mechanic Towing: From Roadside to Expert Repair
If you’re stuck on the side of the road with trailer lighting issues, simply call JL Mobile. We’ll dispatch a tow truck, bring your trailer (and vehicle) directly to our secure shop, and handle everything from diagnostics to repairs. Our tow and repair services cover the Four States region 24/7—making us your partner for emergencies and proactive maintenance.
Contact JL Mobile Today
Don’t risk fines, failed inspections, or unsafe conditions. For strict compliance, expert repairs, and towing that brings you to the best shop in Joplin, trust JL Mobile Truck & Trailer Repair. Call us now at (417) 438-9461 or visit 120 N Prigmor Ave, Joplin, MO.
From trailers that won’t light up to full hydraulic and diesel service, we’re here to keep you rolling—on the road and in our shop!