The answer to 'AC not turning on' is that there are several common causes, including a tripped circuit breaker, a thermostat issue, a problem with the condenser unit, or a lack of power reaching the system. The symptoms may include the AC unit not powering on at all, the fan not running, or the compressor not kicking in.
For simple issues like a tripped breaker or thermostat problem, you may be able to troubleshoot and resolve the issue yourself. However, for more complex problems with the condenser, refrigerant, or internal components, it's best to call in a professional HVAC technician to diagnose and repair the system properly.