Diagnose the fault in a low voltage distribution box by checking for overheating, loose connections, and using voltage testers for safe troubleshooting. In this guide, we'll walk through these. Switches are used to turn lights or electrical devices on and off. After determining that a light bulb is not burned out and a circuit breaker or GFCI is not tripped, the switch may have failed. Always turn off the power before you start any inspection. When a switch stops working, it's essential to identify the cause quickly to avoid the risk of short circuits or prolonged breakdowns.