Heating and Ventilation

Heating and Ventilation

COMPONENT LOCATION









OVERVIEW
Two levels of heating and ventilation are available. High specification vehicles are fitted with a dual zone automatic system, which can provide different temperature settings for the LH and RH sides of the cabin. The dual zone system may also be fitted with a pollution sensor to control the quality of air in the cabin.
Lower specification vehicles are fitted with a single zone manual system.
The heater assembly for both systems is installed on the vehicle center line, between the instrument panel and the engine bulkhead.
The ATC module controls operation of the blower motor via the blower motor control module, which is mounted on the bulkhead side of the heater assembly casing.For additional information, refer to Air Distribution and Filtering Air Distribution and Filtering
For additional information, refer to Air Conditioning Air Conditioning
For additional information, refer to Control Components Control Components
Some vehicles may also be fitted with an auxiliary heater. For additional information, refer to Electric Booster Heater


AUTOMATIC TEMPERATURE CONTROL MODULE





Air distribution and temperature is controlled by the Automatic Temperature Control (ATC) module, which is integral with the control panel. In response to commands from the control panel, the ATC module controls operation of either 3 (single zone) or 5 (dual zone) stepper motors mounted on the heater assembly casing. For additional information, refer to Control Components Control Components

HEATER ASSEMBLY









The heater assembly controls the temperature of the air supplied to the air distribution ducts, as directed by the ATC module. The heater assembly is mounted on the vehicle center line and comprises the following components:
- Blower motor
- Heater core
- Cabin air filter. For additional information, refer to Air Distribution and Filtering Air Distribution and Filtering
- A/C evaporator. For additional information, refer to Air Conditioning Air Conditioning
- Air intake flap and stepper motor. For additional information, refer to Control Components Control Components
- Air distribution flaps and stepper motors. For additional information, refer to Control Components Control Components
- Temperature blend flaps and stepper motors. For additional information, refer to Control Components Control Components
- Electric booster heater (if fitted). For additional information, refer to Electric Booster Heater

Blower Motor
The blower motor comprises an open hub, centrifugal fan powered by an electric motor. Operation of the blower motor is controlled by the ATC module in conjunction with the blower motor control module. The ATC module provides a Pulse Width Modulated (PWM) signal to the blower motor control module based on the required blower speed. The blower motor control module interprets the PWM signal as a blower motor speed and controls the voltage to the blower motor accordingly. For additional information, refer to Control Components Control Components

Heater Core
The heater core provides the heat source to warm the air being supplied into the cabin. The heater core is an aluminum, 2 pass, fin and tube heat exchanger installed across the width of the heater assembly. Two aluminum tubes attached to the heater core extend through the engine bulkhead and connect to the engine cooling system. When the engine is running, engine coolant is constantly circulated through the heater core by the coolant pump. For additional information, refer to Engine Cooling - 3.2L Description and Operation
For additional information, refer to Engine Cooling - 2.2L Diesel

VENTILATION OUTLETS
The ventilation outlets allow the free flow of air through the cabin. The outlets are installed in the LH and RH rear quarter panels, behind the tail lamps.
Each ventilation outlet comprises a grille covered by a soft rubber flap, and is effectively a non-return valve. The flaps open and close automatically depending on the differential between cabin and outside air pressures.

PRINCIPLES OF OPERATION
Operation of the heating and ventilation system is controlled by the ATC module. For additional information, refer to Control Components Control Components