Description

Description

Heating And Ventilation Components:

The heating and ventilation system controls the vehicle's interior heating and air distribution.

The heating and ventilation system consists of two air inlet housings, a heater unit, distribution ducts and a Heater ECU. Fresh or recirculated air flows into the heater unit, from the air inlet housings, assisted by an electric blower in each housing and/or ram effect. In the heater unit the temperature of the air is controlled by servo operated flaps. Additional servo operated flaps then direct the air to front heater and rear vents via moulded distribution ducts. Operation of the flap servos and the blowers is controlled by the Heater ECU.

Air Inlet Housings
LH and RH air inlet housings supply fresh or recirculated air to the air inlets on each side of the heater unit. Fresh air is drawn through the grille at the base of the windscreen and into the plenum, from where it passes through pollen filters into the air inlet housings. Recirculated air is drawn from the vehicle interior through grilles in the air inlet housings. Servo operated flaps in the air inlet housings control the selection of fresh or recirculated air. Each air inlet housing also incorporates a blower consisting of an open hub, centrifugal fan powered by an electric motor.

Heater Unit
The heater unit consists of a housing containing a heater matrix which is connected to the engine cooling system. As water is circulated continuously through the heater matrix, the selection of hot or cold air is controlled by servo operated LH and RH blend flaps directing the air through or around the heater matrix. The LH and RH blend flaps operate independently to allow different temperatures to be set for the LH and RH air vents. The servo operated distribution flaps control the flow of air from the heater unit to the outlet vents. Air distribution is common to both sides of the vehicle interior.

The two temperature servos and the distribution servo each incorporate a feedback potentiometer which provides the Heater ECU with a flap position signal to enable accurate control of air temperature and distribution.

Distribution Ducts
Molded ducts are installed for the distribution of air to the face level vents and the front and rear footwell vents. A corrugated duct directs air to the driver's lap vent. Distribution ducts for the windscreen and side window vents are integrated into the fascia.

Vent assemblies in the fascia allow occupants to control the flow and direction of face level air. Each vent assembly incorporates a thumbwheel to regulate the flow and moveable vanes to control direction. The thumbwheel of the outboard vent assembly on the driver's side also controls the flow of air from the driver's lap vent.

Heater ECU
The Heater ECU comprises an integrated ECU and control panel, and is mounted in the centre console below the in-car entertainment unit. To control the heating and ventilation system, the ECU outputs signals to the flap servos and blowers in response to selections made on the rotary switches and momentary push switches installed on the control panel. In addition to the heating and ventilation system, the Heater ECU also controls the rear screen heater and, where fitted, the windscreen heaters and' the seat heaters. Each push switch on the control panel has a LED to indicate the selections made.

After installation of a new Heater ECU, it must be initialized using Testbook to ensure correct operation of the heating and ventilation system.

Heater ECU Control Panel:

Windscreen Heater Switch
Push switch that operates the windscreen heaters. A timed function that automatically goes off after approximately 4 minutes, or immediately if the switch is pressed again. The switch LED is illuminated while the heater is active.

LH Temperature Switch
Rotary switch that controls the temperature of the air to the LH side of the vehicle interior:
^ Driver's side temperature control is dominant over passenger's. The temperature set by the passenger is restricted to a tolerance band of 6° C (11° F) above or below that set by the driver.
^ The control is overridden when demist programme switch is selected.

Blower Switch
Rotary switch that simultaneously controls the speed of both blowers:
^ Clockwise rotation progressively increases blower speed. Anti-clockwise rotation progressively decreases blower speed.
^ The control is overridden when demist programme is selected.

RH Temperature Switch
Rotary switch that controls the temperature of the air to the RH side of the vehicle interior. Operates the same as the LH temperature switch.

Fresh/Recirculated Air Switch
Push switch that simultaneously controls selection of fresh or recirculated air in both air inlet housings:
^ Demist programme overrides recirculated air selection.
^ First press of switch selects recirculated air. Switch LED illuminated while recirculated air selected.
^ A second press of the switch restores fresh air selection. Switch LED extinguished while fresh air selected.

RH Front Seat Heater Switch
Push switch that controls the RH front seat heaters. Operation is independent of the heating and ventilation system. The heaters remain active until the switch is pressed again. The switch LED is illuminated while the heaters are on.

Demist Mode (PROG) Switch
Push switch for initiating automatic demist mode:

^ Air inlets set to fresh air.
^ Blower speeds set to optimum.
^ LH and RH temperatures set to maximum.
^ Distribution set to windscreen and side windows only.
^ Rear screen heater selected on and rear screen heater switch LED illuminated.
^ Windscreen heaters selected on and windscreen heater switch LED illuminated.

Windscreen/Side Window Distribution Switch
Push switch that sets air distribution to windscreen and front side window vents.

Windscreen/Side Window And Footwells Distribution Switch
Push switch that sets air distribution to windscreen, front side windows and footwell vents.

Footwell Distribution Switch
Push switch that sets air distribution to the footwell vents.

Face And Footwell Distribution Switch
Push switch that sets air distribution to the face level, driver's lap and footwell vents.

Face Distribution Switch
Push switch that sets air distribution to the face level and driver's lap vents.

LH Front Seat Heater Switch
Push switch that controls the LH front seat heaters. Operation is independent of the heating and ventilation system. The heaters remain active until the switch is pressed again. The switch LED is illuminated while the heaters are on.

Rear Screen Heater Switch
Push switch that operates the rear screen heater. A timed function that automatically goes off after approximately 15 minutes, or immediately if the switch is pressed again. The switch LED is illuminated while the heater is active.

The exterior mirror heaters are activated for approximately 10 minutes when either the windscreen or rear screen heaters are activated. There is no active indicator or independent control for the exterior mirror heaters.

Heater ECU Connectors:

Heater ECU Connector Pin Details:

Heater ECU Connector Pin Details: