Carrier air conditioner will not turn ON at all (no lights, no response)

Safety: If you are not comfortable with electrical work, contact a professional. Always turn OFF the main breaker before opening electrical panels.

• Step 1 – Check thermostat/remote: Ensure batteries are good and the mode is set to COOL with a temperature below room temperature.
• Step 2 – Check breakers: Inspect the main electrical panel for tripped breakers labeled for the AC (indoor air handler and outdoor condenser). Reset once if tripped.
• Step 3 – Inspect outdoor disconnect: Verify the disconnect near the outdoor unit is ON and that any pull-out is fully inserted.
• Step 4 – Look for indicator LEDs: On some Carrier units, small LEDs on the indoor or outdoor PCB indicate power. If none are lit, the board may not be receiving power.
• Step 5 – Technician service: If power is present at the unit but it remains dead, a technician should test the transformer (for ducted systems) and PCB power supply.