The base heater system is designed to provide heating, ventilation, windshield defrosting, side window defogging, and on some vehicles, heating directly to the rear seat area.
The heater and fan assembly blower regulates the airflow from the air inlet for further processing and distribution.
The heater core transfers the heat from the engine coolant to the inlet air.
The temperature door regulates the amount of the air that passes through the heater core. The temperature door also controls the temperature of the air by controlling the mix of the heated air and the ambient air.
The mode door regulates the flow and the distribution of the processed air to the heater ducts and to the defroster ducts.
Console-Mounted Heating and Ventilation Panel
The Rotary Temperature Control Knob
| • | Raises the temperature of the air entering the vehicle by rotation toward the right, or the red portion of the knob |
The Rotary Blower Control Knob
| • | Turns ON to operate the blower motor at 4 speeds |
| • | Turns OFF to stop the blower |
| • | Operates completely independently both from the mode control that regulates the defroster door and from the temperature control knob |
| • | Changes the fan speed in any mode and at any temperature setting |
The Rotary Mode Control Knob
| • | Actuates by electrical motor |
| • | Regulates the air distribution between the windshield, the instrument panel, and the floor vents |
The Rear Window Defogger Push Knob
| • | Controls the rear window defogger |
| • | Turns ON the rear window defogger when the push knob is pressed and the indicator lamp is illuminated |
The A/C Push Knob, if the vehicle is equipped with air conditioning
| • | Controls the air conditioning (A/C) |
| • | Turns the A/C ON when the push knob is down -- However, if the blower control knob is OFF, the A/C system is OFF, regardless of the position of the A/C knob. |
The Fresh Air Control
| • | Operates by electrical motor |
| • | Draws in outside air when the knob is off |
| • | Recirculates inside air when the knob is sown and the indicator lamp is illuminated |
A/C System - Typical
