Automatic HVAC System Description: Controller
The operation of the A/C system is controlled by the switches on the control head. This console-mounted heating and ventilation system consists of control knobs and a vacuum fluorescent display (VFD) indicating the status of the control settings selected.
Temperature Control Push Knobs
- Raise the temperature of the air entering the vehicle by turning the rotary switch clockwise (red arrow direction).
- Lower the temperature of the air entering the vehicle by turning the switch counterclockwise (blue arrow direction).
- Actuate the air mix door by an electric motor.
- Vary the mix of the air passing through the heater core with the air bypassing the core.
- Each press of a switch changes the set temperature by increments of 0.5°C (1°F). This is shown in the temperature window on the function display.
Vacuum Fluorescent Display (VFD)
- Temperature setting-Indicates the temperature set with temperature control knob.
- Auto status-Indicated whether the system is operating in the full automatic mode or manual mode.
- Defroster icon-Indicates manual selection of full defrost mode.
- Mode-Indicated by icon, the mode chosen by the system in auto (or by the operator in manual) is shown by an illumination arrow indicating the air path.
- A/C-A snowflake icon indicating whether the A/C is ON or OFF.
- Fan speed-Indicates the fan speed by illuminating a bar based on the segment at the front, for low speed, and adding additional segments in order up to the eighth, for high speed.
Seven Additional Push Knobs
- Full defrost-Causes the mode motors to direct all air to the windshield and aide window outlets for maximum defrosting.
- Air intake-Switches between fresh air intake, the default, and recirculating air. Airflow arrows on the display indicate the mode in effect.
- Full auto switch-Maintains the set temperature automatically. In this mode, the fully automatic temperature control (FATC) system controls the following:
- The air mix door motor
- The mode door motor
- The blower motor speed
- The inlet air door motor
- A/C ON/OFF
- OFF switch-Turns the automatic air conditioning and fan control off.
- Mode switch-Allows manual selection of the airflow direction.
- Selection is shown on the function display.
- Each time the mode switch is pressed, the next function is displayed.
- A/C switch-Allows manual selection and control of the air conditioning function.
- Defogger switch-Turns ON the electric defogging heater in the rear window and the outside rearview mirrors, if the vehicle is equipped with heated mirrors.
- Fan control rotary knob-Allows for manual selection of the fan speed.