CAPACITOR

• You hear a humming or buzzing from the outdoor unit when the AC turns on.
• The compressor or fan motor doesn't actually start running.
• A failed run capacitor can't deliver the starting boost the motor needs.

Tip: A humming compressor with a bulging capacitor is one of the most common AC repairs. Replacement takes about 15 minutes.

• Indoor vents blow air that isn't cold, even though the system is running.
• The outdoor fan may be spinning but the compressor isn't engaging.
• Without the compressor running, refrigerant can't circulate to cool the air.

• Thermostat is calling for cooling but nothing happens at the outdoor unit.
• No humming, no fan — the unit is completely unresponsive.
• This can indicate a failed start capacitor or a dual-run capacitor.

• AC works sometimes but shuts off randomly or takes a long time to start.
• Cooling is inconsistent throughout the day, especially in peak heat.
• A weak capacitor may still work intermittently before fully failing.

• The condenser fan turns sluggishly or won't start on its own.
• If you push the fan blade with a stick, it begins spinning — this points directly to a bad capacitor.
• The fan motor is fine, but it can't get the starting torque it needs.

Warning: Never touch fan blades with your hand. Use a long stick or screwdriver handle through the grille.

• The top of the capacitor is bulging or domed instead of flat.
• You see oily residue leaking from the base or sides.
• A visually damaged capacitor should be replaced immediately — it's a confirmed failure.