Fresh Air/Recirculated Air Control Button

Fresh air/recirculated air control button uses vacuum to select airflow source. With control at fresh air setting (extended), vacuum is applied to outside door vacuum motor. Outside air is then allowed to enter and pass through heater core. With control at recirculated air setting (depressed), vacuum is removed from outside door vacuum motor and air is recirculated inside passenger compartment. Recirculated air position is used to achieve maximum heating and/or while driving on dusty roads. See Figure and Figure .