The answer to 'why is my air filter not turning on' is that there could be several common causes, such as a tripped circuit breaker, a faulty air filter switch, or a problem with the air handler unit. If the air filter is not turning on, it may indicate an electrical issue that requires troubleshooting.
First, check your circuit breaker to ensure it has not tripped. If the breaker has tripped, reset it and see if that resolves the issue. If the breaker continues to trip, there may be an underlying electrical problem that requires the attention of a professional HVAC technician.