If you have a pit light that is no longer turning on, there are a few potential causes to investigate. Pit lights are powerful lights designed to illuminate underground areas like mines and excavation pits. When a pit light stops working properly, it’s important to troubleshoot the issue so you can get the light operational again and safely light your working area.
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Check the Power Source
The first thing to check with a non-working pit light is the power source. Start by ensuring the battery is charged if you have a portable cordless model. Plug the charger in and give the battery several hours to fully recharge. If the pit light has internal batteries, try replacing them with fresh ones. For lights that have a power cord, inspect the entire length of the cord and plug for damage. If there are any cuts, exposed wiring, or bent plug prongs, this could be interrupting the flow of electricity.
Try plugging the pit light directly into a known good power source like a working wall outlet. If the light still doesn’t turn on, the issue is probably with the light itself rather than the power supply. For lights wired directly to your vehicle’s battery, check the condition of the wiring and connection points. Clean any corrosion at the terminals and tighten the connections. Have the battery tested to confirm it is still holding a charge.
Check the Bulb
If the pit light has power but still won’t turn on, the next thing to examine is the bulb itself. Make sure the bulb is securely seated in the light fixture. If it uses screws or clips to hold it in place, tighten them or reseat the bulb. Check that the contacts on the base of the bulb are clean and not corroded. Gently clean them with fine sandpaper if needed to remove dirt or oxidation.
Try replacing the bulb with a known good one that matches the wattage and design for your particular pit light model. Inspect the bulb for broken filaments or blackening inside the glass, both signs that the bulb has burned out. Never touch the glass of halogen bulbs with your bare hands, as oil from your skin can cause them to fail prematurely.
Common Pit Light Bulb Types
| Bulb | Characteristics |
|---|---|
| Halogen | Get very hot, produce bright white light, prone to burning out |
| Xenon | Produce very bright white light, long bulb life |
| LED | Long lifespan, energy efficient, durable |
| Incandescent | Cheap, less bright than other options, don’t last as long |
If the bulb is fine and the pit light still won’t illuminate, there may be an issue with the light’s wiring, switches or internal components.
Inspect the Lens and Housing
Take a close look at the lens cover and external housing of the pit light. Cracks, damage or broken seals can allow moisture, dirt and debris inside the light that can cause electrical and mechanical issues. Replace any cracked lenses and have the light’s waterproof seals repaired if they appear compromised. This will help prevent short circuits and corrosion.
Make sure the lens is clean and not obstructed by mud or buildup that could be blocking the beam. Carefully wipe it down or use a hose to wash away any debris. Rotate or adjust any focusing knobs or dials to ensure the housing is not merely misaligned.
Check Internal Workings
If the external workings of the pit light seem fine, the issue may be in the internal wiring, switches and components. Open up the light housing to inspect these parts. Look for signs of loose, disconnected or frayed wires. Tighten any loose screw terminals and reconnect any wires that have come loose. Search for fried or cracked insulation and replace any damaged wiring.
Examine the toggle or rocker switches that control the light. Flip the switches back and forth briskly to clear out any dust or grit that may be obstructing their operation. Switches can also simply wear out over time. Substitute a known good switch to see if that restores operation. Inspect solder joints for cracks and reflow any that look suspect.
Check that the internal lamp housing is intact and not cracked or warped, which could disrupt electrical contacts. Make sure no connectors have vibrated loose inside the assembly. Tighten everything securely. Look for signs of overheating like melted plastic or rubber. This could indicate an overloaded circuit, short circuit or failing component.
Common Pit Light Internal Components
| Component | Purpose |
|---|---|
| Wiring | Transmits power throughout light |
| Fuse | Protects against current spikes |
| Ballast | Regulates power to bulb |
| Switch | Turns light on and off |
| Transformer | Steps up or down voltage |
| Capacitors | Stores electrical charge |
Replacing any damaged or defective internal components may return your pit light to working order. Use replacement parts specifically made for your light model.
Inspect the Wiring Harness
If your pit light is vehicle-mounted, also carefully inspect the wiring harness that connects the light to your vehicle. Look for pinched, cut, or crimped wires all along the length of the harness. Vibration or improper mounting can damage the harness over time. Check that all plugs and terminals are still securely attached with no looseness or corrosion. Clean any dirty or oxidized electrical contacts in both the harness and the vehicle’s power system.
Ensure the harness is properly rated for the wattage draw of the pit light and not undersized. Use a multimeter to check for continuity through each wire in the harness. If any show an open circuit, that individual wire is broken somewhere and the harness will need to be repaired or replaced.
Check the Vehicle Charging System
For pit lights powered through your vehicle’s own electrical system, charging system issues can cause problems. Have the alternator and batteries tested to make sure they are still functioning properly. The alternator recharges the batteries while the vehicle is running. If it fails, the batteries may die prematurely. Weak batteries can fail to provide enough power to operate a pit light consistently.
Clean and tighten all charging system connections from the alternator to the battery terminals. Look for signs of corrosion which can cause excessive resistance. Also inspect the battery ground strap and connection to the vehicle chassis. Have the charging voltage regulated if it is too high or too low.
Test Electrical Load and Supply
Use a multimeter or test light to check if power is actually reaching your pit light when turned on. Start at the power source and test at each connection point back toward the light. This will help you isolate the exact location of any electrical interruption. Check the fuse box and replace any blown fuses. For hardwired lights, look for tripped circuit breakers or blown fuses in the breaker panel.
High wattage lights can sometimes overload circuits, especially if multiple lights are on the same circuit. Calculate the total wattage of all lights on a circuit and compare it to the circuit capacity. Redistribute lights across additional circuits if overloaded. Voltage drop from undersized wiring can also cause dim lighting and other problems.
Inspect Mounting Points
Make sure pit lights are securely mounted to prevent excessive vibration. Loose mounting can gradually cause fasteners to loosen and wires to disconnect or short out. Tighten any loose brackets, bolts, straps, clips, and other attachment points. Add washers or lock washers to prevent fasteners backing out over time.
Check that mounting orientation allows proper cooling. Lights should be mounted base down when possible so heat can escape upward. Add a heat shield above if mounted sideways. Prevent clustered installation with other hot equipment that can cause overheating issues.
Consider Moisture Issues
Moisture getting into light housings can lead to corrosion, electrical shorts, and breakdown of insulation. Even moisture from excessive humidity can cause problems over time. Look for evidence of water intrusion like mineral deposits, fogging inside the lens, or rust. Repair any cracked or missing gaskets, seals, and o-rings that protect sensitive components.
Prevent moisture issues by mounting lights pointed down to avoid rainwater entry. Protect portable lights from wet ground with a waterproof cover or stand. Avoid using underground where condensation can form from temperature differences between surface and below ground.
Conclusion
Troubleshooting and fixing a non-working pit light is usually achievable with some basic electrical tests and component replacement. Start by methodically checking the power supply, bulb, wiring, and connections. Inspect all parts of the light assembly and vehicle charging system too. Replace any damaged wiring, bad switches, or burned-out bulbs. With persistent issues, the problem may lie with the internal circuitry and require professional electrical troubleshooting. Get your pit light illuminating properly again so you can work safely and productively even in the darkest environments underground.