The part(s) or condition(s) listed below for the symptom Air conditioner coils freezing are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
If the air filter becomes clogged with dirt, it restricts airflow over the evaporator coils. If the airflow is reduced, the evaporator coils get too cold, which then causes the humidity in the room to condense on the coils and freeze. As frost accumulates on the coils, the frost restricts the airflow even more. Eventually, the entire evaporator coil assembly will frost over, causing the airflow to be completely restricted. If the air filter is dirty, replace it.
If the air conditioner coils are freezing in only one area, there may be a sealed system (or refrigerant) leak. This is normally a very expensive repair. Repairs to the sealed system must only be performed by a licensed technician.
An air conditioner dual shaft fan motor is the component that spins the fan blade and blower wheel to both draw air into the unit and force it through the front vent and out the rear condenser coil. If the fan motor is burned out, the air won't be circulated which can cause the coils to freeze and the condenser and compressor to overheat. You can use a multimeter to determine if power is reaching the fan motor. If power is reaching the motor, but it doesn't run, the component will need to be replaced.
Air Filter
An air conditioner fan motor is the component that spins the fan blade or blower wheel to circulate the air. If one of the fan motors is burned out, the air won't be circulated properly which can cause the coils to freeze. You can use a multimeter to determine if power is reaching the fan motor. If power is reaching the motor, but it doesn't run, the component will need to be replaced.