The answer to 'my dimmer switch won't turn on' is that there could be several common causes, including a faulty dimmer switch, a problem with the electrical wiring, or a tripped circuit breaker. Symptoms may include the dimmer switch not responding when turned, the lights not dimming properly, or the switch feeling loose or damaged.
To troubleshoot, first check the circuit breaker to ensure it has not tripped. If the breaker is fine, the issue is likely with the dimmer switch itself. You can try replacing the switch, but if you are not comfortable working with electrical components, it's best to call a licensed electrician to diagnose and repair the problem.