Turn off power to the AC unit at the thermostat and breaker
Remove the access panel to reach the indoor evaporator coil
Locate the coil and inspect it for dust, dirt, and debris
Vacuum loose debris with a soft brush attachment
Spray the coil with a no-rinse evaporator coil cleaner
Let the cleaner sit for the recommended time on the product label
Wipe accessible surfaces gently with a soft cloth or brush
Clean the drain pan and clear any standing water
Check and clean the condensate drain line if needed
Reinstall the access panel securely
Restore power to the unit
Replace the air filter if it is dirty
Schedule professional cleaning if the coil is heavily clogged or hard to access