Your AC unit is powered by electricity, so it's essential to check your home's circuit breaker panel to ensure everything is in order. If the AC unit's breaker has tripped, it will disrupt power flow to the system, causing it to stop working. Locate the breaker for your AC unit and check if it has tripped. If it has, reset it and see if the AC powers back on. However, if the breaker continues to trip, it could indicate a more significant electrical issue that requires professional attention.