Why Is My AC Not Turning On?
If your AC will not turn on at all, check these in order: thermostat has power and is set to COOL, both circuit breakers (indoor and outdoor) are not tripped, the safety float switch has not been triggered by a full drain pan, and the outdoor disconnect box fuses are intact. These four checks resolve the problem about half the time without needing a technician.
THE DETAILS
A dead thermostat is the simplest cause. If the screen is blank, replace the batteries or check the breaker that powers it.
Tripped breakers are extremely common. Your AC has two breakers — flip both fully off, wait 30 seconds, then back on.
The condensate safety switch shuts the AC down if the drain pan fills with water to prevent water damage. Clear the drain line to fix this.
The outdoor disconnect box contains fuses that can blow during power surges. A tech can replace these in minutes.
A failed capacitor prevents the compressor and fan from starting. You may hear clicking or humming from the outdoor unit. This is one of the most common and affordable repairs.
🔧 WHEN TO CALL A PRO
If all breakers are on, the thermostat has power, and the AC still will not start, call a pro. Capacitor, contactor, or control board failures need professional repair.