My AC unit isn’t turning on, what could be the cause of this?

Tripped Circuit Breakers: as one of the most common reasons of why your unit won’t turn on, a tripped circuit breaker is caused when the circuit overloads

Drainage Problems: Clogged condensate drains or an overflowed drain pan can cause your system to repeatedly shut off.

Faulty Compressor: Your unit will not turn on when your compressor/motor stops working. 

Dirty Filter: As the most common reason your AC system may have issues, it is recommended to change or clean your filter every 3-4 months (or once a year depending on the type of filter you have) to maximize airflow and keep energy costs low. A dirty filter can cause other problems besides increased energy consumption such as causing a burnout to the motor (the clogged filter causes a strain on the system) or clogging the air ducts.

Thermostat Failure: Thermostat failures can cause you system to short cycle. Thermostat sensors can be knocked out of place causing your system to run constantly.