When your air conditioner stops operating, it might be a sign of a serious problem or it could be as simple as a blown fuse or tripped circuit breaker.
If your air conditioner isn't working, first check outdoors to see if the condenser is operating. Check that the unit is plugged in and that your thermostat is correctly set. It may seem obvious, but check to make sure your thermostat is set to cool.
If your air conditioner runs and your thermostat is adjusted correctly, but your system still doesn't cool, it might be due to a clogged air condenser. The first step is to inspect the exterior unit and clear up any trash or weeds that are obstructing air flow.