The answer to 'why is my switch not working' is that there are several common causes, including a tripped circuit breaker, loose or damaged wiring, or a faulty switch. The most common symptoms are the switch not turning on the light or appliance as expected, or the switch feeling loose or not clicking properly.
To troubleshoot, first check the circuit breaker to ensure it has not tripped. If the breaker is fine, use a voltage tester to check for power at the switch. If there is no power, the issue may be with the wiring. If there is power but the switch is still not working, the switch itself may be faulty and need replacement. For any electrical work, it's best to call a licensed electrician if you are not comfortable working with electricity yourself.