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 to select operating modes, a fan speed increase/decrease switch, the rear defog control switch, and a vacuum fluorescent display panel. When the parklamps or headlamps are turned on, the buttons and switches are illuminated.

When any button on the heater and A/C control assembly is pressed the complete status of the HVAC system will be displayed. The display will indicate the status of the blower speed, mode and set temperature.

Mode Selector Button
The heater and A/C control has a mode selector button for the following modes:

^ OFF
^ AUTO.
^ MID.
^ VENT
^ MID/FLOOR.
^ FLOOR.
^ DEFOG.

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.

Temperature Increase/Decrease Button
With the system in any mode but OFF and the SET temperature is between 18°C (65°F) and 29°C (85°F), pressing the increase or decrease end of the switch once increases or decreases SET temperature one degree. If the decrease end of the switch is pressed with the SET temperature at 18°C (65°F), SET temperature drops immediately to 15°C (60°F). if the increase end of the switch is pressed with SET temperature at 29°C (85°F), the SET temperature jumps immediately to 32°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 air temperature) to bring the passenger compartment temperature to the new SET temperature.
With the system in the OFF mode, pressing either end of the temperature switch causes the system to turn on in the AUTO mode. The system displays the outside temperature approximately 10 seconds after the last change on the temperature knob, as well as when the system is in the OFF mode.

Fan Speed Increase/Decrease Button
The fan speed increase/decrease switch is used to manually change fan speed. Pressing the increase end of the fan speed switch once, increases the fan speed one level. Holding the increase end of the switch increases the fan speed until the switch is released or maximum fan speed is reached. Pressing the decrease end of the switch decreases fan speed in the same manner.

If the system is operating under AUTO fan speed control, moving the fan speed switch causes AUTO fan speed control to stop and manual fan speed control to begin. Fan speed remains constant, unless the increase/decrease switch is pressed again.

With the system in OFF mode, pressing either end of the fan speed switch causes the system to turn on in the AUTO mode with AUTO fan speed control.

Vacuum Fluorescent (VF) Information Display Panel
The VF panel provides system operating information for the driver.

The display panel has a three digit temperature display and the letters °C and °F appear on the display. The °C is illuminated when metric units are requested. The °F is illuminated for temperature display in English units. The words EXT TEMP and AUTO appear to the left of the temperature display. EXT TEMP is illuminated whenever outside temperature is displayed. AUTO turns on when AUTO mode is selected.

The blower speed is displayed in the form of the number of bars illuminated. One bar illuminated indicates low blower speed. Six bar illuminated indicates high blower speed.

When the system is operating in AUTO mode, with AUTO fan speed control, no indicators are illuminated. Instead, the words AUTO illuminates. When the system is turned OFF, the fan speed display area is blank and the outside air temperature is displayed.