METHOD OF CONTROLLING AUTOMOTIVE HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM

A method of controlling an automotive heating, ventilation, and air conditioning (HVAC) system includes steps of: comparing, by a controller, a voltage applied to a mode door actuator with a first operating voltage, a second operating voltage, and a third operating voltage when a driving condition of a vehicle meets an external condensation occurrence condition; and controlling, by the controller, a defrost mode door to close a defrost outlet or adjust an opening degree of the defrost outlet to be less than a reference opening degree when the voltage applied to the mode door actuator is greater than or equal to the first operating voltage, where the defrost outlet directs air toward a front windshield, and the reference opening degree is an opening degree of the defrost outlet which has been set when the driving condition of the vehicle does not meet the external condensation occurrence condition.