Heater and A/C Control Assembly
The heater and A/C control allows the vehicle operator to communicate with the electronic A/C system. The heater and A/C control includes soft touch buttons for the various system operating modes, a temperature increase/decrease knob, a fan speed increase/decrease knob and a vacuum fluorescent (VF) information display panel. When the parklamps or headlamps are turned on, the buttons and knobs are illuminated.
Passenger Climate Control
The passenger climate control consists of a rotary potentiometer with seven positions. The control assembly communicates directly with the heater and A/C programmer through varying an analog voltage.
Turning the knob to the right or left causes the system to begin operating in the dual zone mode. The passenger can raise or lower passenger side discharge air temperature by turning the knob in the appropriate direction.
Discharge air temperatures could be different from side to side when not in dual zone mode, due to greater sun load on one side of the vehicle.
Temperature Knob/Button
With the system in any mode but OFF and SET temperature between 18.9°C and 28.9°C (66°F and 84°F), turning the temp knob one detent in either direction, or pressing the warm or cold button, increases or decreases SET temperature one degree. If the knob is turned in the decrease direction or cool button is pressed, to achieve the lowest setting, with the SET temperature at 18.3°C (65°F), SET temperature drops immediately to 15.6°C (60°F.) If the knob is turned in the increase direction or the warm button is pressed to achieve the highest setting, with SET temperature at 29.4°C (85°F), SET temperature will jump immediately to 32.2°C (90°F).
An increase or decrease of the SET temperature signals the heater and A/C programmer to take the steps necessary (change blower speed, change air discharge location, change discharge temperature) to bring the passenger compartment temperature to the new SET temperature.
With the system in OFF mode, turning the temperature knob in either direction or pressing your warm or cool button, causes the system to turn on in the AUTO mode.
Fan Speed
The fan speed increase/decrease knob is used to manually change fan speed. Turning the fan speed knob in the increase (clockwise) direction one detent increases fan speed one level. Turning the fan speed knob all the way in a clockwise direction will increase the fan speed to the maximum. Turning the fan speed knob in the decrease direction will decrease fan speed in the same manner as increase.
If the system is operating under AUTO fan speed control, turning the fan speed knob in either direction, causes AUTO fan speed control to stop and manual fan speed control to begin. Fan speed remains constant, unless the speed control knob is turned again.
With the system in OFF mode, turning the fan speed knob in a clockwise direction causes the system to turn on in the AUTO mode with AUTO fan speed control.
Mode Selector Buttons
The heater and A/C control has a mode selector button for each operating mode (OFF, AUTO, PASS, UPPER, LOWER, FRONT DEFROST, DEFOG, BI-LEVEL, A/C and RECIRC).
Pressing any button except AUTO tells the heater and A/C programmer to set air intake point, set air discharge points and activate or de-activate the A/C compressor, according to the mode selected.
Pressing AUTO tells the heater and A/C programmer to select the appropriate air intake and discharge points and activate or de-activate the A/C compressor, according to the operator selected SET temperature and information provided by the system's network of sensors.
A/C Button
The A/C button controls whether or not the A/C compressor can be turned on or off in manual mode. When pressed the A/C LED is illuminated. The LED is also illuminated if DEFOG or FRONT DEFROST are selected. A/C cannot be deselected during DEFOG or FRONT DEFROST operation.
UPPER Button
When the UPPER button is pressed, the LED in the switch will illuminate, and the currently SET temperature is displayed for five seconds. The UPPER button directs the air out the vents.
BI-LEV Button
When the BI-LEV button is pressed, the LED in the switch will illuminate, and the currently SET temperature is displayed for 5 seconds. The BI-LEV Button directs air out the heater and vent outlets.
LOWER Button
When the LOWER Button is pressed, the LED in the switch is illuminated and the SET temperature is displayed for five seconds. The LOWER Button directs air out the floor outlets.
DEFOG Button
When the DEFOG button is pressed, the LED in the DEFOG and A/C button is illuminated, and the SET temperature is displayed for five seconds. The DEFOG switch directs air out both the lower and defrost outlets.
FRONT DEFROST Button
When the FRONT DEFROST button is pressed, the LED in the switch is illuminated and the SET temperature is displayed for five seconds. The FRONT DEFROST button directs air to the windshield. This is a manual only mode.
RECIRC Button
When the RECIRC button is pressed the LED will illuminate. This button will operate in all modes except DEFOG and FRONT DEFROST The RECIRC switch causes the air to be recirculated through the HVAC system from the passenger compartment.
RECIRC will operate for approximately 10 minutes then deactivate. Manual mode changes and ignition cycles will also deactivate the recirc function.
VACUUM FLUORESCENT (VF) INFORMATION DISPLAY PANEL
The VF panel provides system operating information for the driver.
A three digit temperature readout is located near the center of the display. With the system in OFF mode, outside temperature is displayed continuously.
When any other mode is selected, SET temperature is displayed for five seconds; the display then returns to the outside temperature. Turning the temperature knob or pressing any mode button except OFF while the system is operating also causes SET temperature to be displayed for five seconds.
SYMBOLS
Arrows appearing in the center of the display are used to indicate air discharge location relative to the seat (Pontiac) or relative to the words windshield, MID and FLOOR (Buick). An upper (windshield) discharge arrow, a lower (floor level) discharge arrow, a middle (instrument panel) discharge arrow, or a combination of these discharge arrows may be illuminated, depending on the current system operating mode. This area is blank if the system is turned OFF. The display then returns to outside temperature. Turning the temperature knob or pressing any mode button except OFF while the system is operating also causes SET temperature to be displayed for five seconds.
The word AUTO is located to the right of the temperature display. With the system operating in AUTO mode, AUTO is illuminated.
The word OFF is located to the left of the temperature display. With the system off the OFF and OUTSIDE indicators will be illuminated with the outside temperature being displayed. The system will wake up from the OFF mode when any button or rotary switch is activated except for the RECIRC, AC or REAR DEFOG buttons.
At the far left of the display is a fan speed bar graph which is activated when fan speed is in manual mode. The number of bars illuminated indicates fan speed. When the fan is operating at its lowest speed, one bar is illuminated. When operating at maximum speed, all bars are illuminated.
When the system is operating in AUTO mode with AUTO fan speed control, no bar segments are illuminated.
When the system is turned OFF, the fan speed display area is blank.