The Sub-Zero 3211RFD freezer fan should blow air across the evaporator coil. The fan's purpose is to circulate cold air inside the freezer, ensuring even cooling and maintaining a consistent temperature throughout the compartment. As the fan blows air across the evaporator coil, it helps in the heat exchange process. The coil absorbs heat from the freezer's interior, converting it back into cold air. This continuous cycle allows the freezer to maintain the desired low temperature, ensuring efficient freezing and optimal preservation of food items. By directing the airflow across the evaporator coil, the freezer fan plays a crucial role in providing reliable cooling performance.