Control Assembly: Description and Operation

RECIRCULATION SWITCH
The Recirculation Switch is a momentary contact switch. Toggling the switch ON results in the A/C - Heater Control Module signaling the actuator to close the fresh-air door. Toggling the switch OFF results in the A/C - Heater Control Module signaling the actuator to open the fresh-air door. The switch LED illuminates when the switch is ON. When the Power Switch is OFF, the A/C - Heater Control Module closes the fresh-air door to prevent outside air from entering the passenger compartment. The recirculation mode will cancel whenever defrost is requested. Pressing the Recirculation Switch while in defrost mode will illuminate the Recirculation Switch LED, but only while the button is pressed. Under this circumstance, the recirculation request will be denied and the fresh-air door will remain in the fresh position. All door positions are determined relative to the number of commutator pulses required to provide full travel of the door. On command, the A/C - Heater Control Module runs the actuator for the number of pulses corresponding to the desired door position.

BLEND SWITCH - SINGLE ZONE
The single, rotary Blend Switch has multiple detents to control the full range of temperature that the system can produce in any mode. Rotating the switch results in the A/C - Heater Control Module signaling the actuator to move the blend door. All door positions are determined relative to the number of commutator pulses required to provide full travel of the door. On command, the A/C - Heater Control Module runs the actuator for the number of pulses corresponding to the desired door position.

BLEND SWITCH - DUAL- AND THREE-ZONE
The dual, sliding Blend Switches have multiple detents to control the full range of temperature that the system can produce in any mode. On Dual-Zone systems, the upper slide pot controls the driver-side blend door, while the lower slide pot controls the passenger-side blend door. On Three-Zone systems, the upper slide pot controls the driver-side blend door and, when activated, the Rear A/C - Heater Unit Blend Door. The lower slide pot controls the passenger-side blend door. Sliding the switch resuits in the A/C - Heater Control Module signaling the actuator to move the blend door. All door positions are determined relative to the number of commutator pulses required to provide full travel of the door. On command, the A/C - Heater Control Module runs the actuator for the number of pulses corresponding to the desired door position.

REAR BLOWER REAR CONTROL
Blend Switch
The rotary Blend Switch controls the full range of temperature that the rear system can produce in any mode. Rotating the switch results in the A/C - Heater Control Module signaling the actuator to move the blend door. A low temperature setting directs airflow to the overhead outlets, while a high temperature setting directs airflow to the floor outlets. All door positions are determined relative to the number of commutator pulses required to provide full travel of the door. On command, the A/C - Heater Control Module runs the actuator for the number of pulses corresponding to the desired door position.