How are the vents controlled on a 96 corsicas defrost by vacuum or actuator?

On a 1996 Chevrolet Corsica, the vents for the defrost system are controlled by a vacuum-operated actuator. When the defrost setting is selected, engine vacuum is used to move the actuator, which in turn shifts the air distribution doors to direct airflow to the windshield. This vacuum control system allows for precise operation of the HVAC system’s venting functions. If there are issues with the defrost operation, it may be related to vacuum leaks or actuator failure.