The answer to 'switch not working' is that a switch not working is often caused by a loose connection, a faulty switch, or a problem with the wiring. Common symptoms include the switch not turning the light or appliance on or off, or the switch feeling loose or wobbly.
If the switch is not working, first try tightening the screws that hold the switch in place. If that doesn't fix it, the switch may need to be replaced. This is usually a simple DIY task, but if you're not comfortable working with electrical wiring, it's best to call a licensed electrician to diagnose and repair the issue.