System Overview
Heating And Ventilation UnitThe heating and ventilation unit controls the air distribution and heating to the vehicle interior. The blower unit controls the volume of air supplied and the air conditioning module provides refrigerated and dehumidified air. This system is split right and left allowing for improved temperature control.
1. Fresh air inlet
2. Recirculation air inlet
3. Air outlets screen de-mist
4. Air outlet face level vents
5. Air outlets front footwells
6. Air outlets to rear footwells
7. Blower motor relay
8. Fresh/recirculation air door servo motor
9. Multiplug connector, servo motors
10. Multiplug connector, blower to heater unit
11. Resistor unit - blower speed
Heater And Ventilation Operation
The heating and ventilation system contains a heater core connected to the engine cooling system and a 4-speed fan for air distribution. Engine coolant is circulated through the heater matrix continuously.
NOTE: Except when the temperature controls are set to COLD on early production Discovery and RR Classic.
Recirculated Air
When the recirculation switch is pressed, servo motor operates and fully closes the fresh air intake.
Fresh Air
When the recirculation switch is returned to the OFF position, the electrical servo motor returns and fully opens the fresh air intake door.
Heated Air
Vent temperature is controlled by the temperature controls which move the air direction and temperature blend doors independently to increase or decrease the volume of air flow through the heater core.
NOTE: When both controls are in the COLD position, the heater core valve is turned off.
Face Vent Flap
Control at face level door fully open, all other vents closed. Control at face and foot level: doors half open.
De-mist Vent Door
Control at de-mist: door fully open, all other vents closed. Control at de-mist and foot level: doors half open.
Location Of Air Vents
The temperature of air supplied to each vent is controlled by the heater.
NOTE: Vent (1) is designed to keep the audio unit cool. There is no air flow from this vent.
Face Level Vents
Each vent can be opened or closed by rotating the thumbwheel - left to close, right to open. Direct the flow of air by moving the control in the center of the louvers.
Heater Controls
1. Temperature Controls:
The left control varies air temperature from the vents on the left side of the vehicle. The right control adjusts air temperature from the vents on the right side.
Rotate each control clockwise (towards the RED segment) to increase the air temperature or counter-clockwise to decreases the temperature.
2. Air Distribution control:
Rotate to select the required distribution of air:
Face Level Vents Only:
Face And Foot Level Vents:
Foot Level Vents, Also Provides Some Air To The Windshield:
Foot Level And Windshield Vents:
Windshield Vents Only:
3. Air Blower Switch
Move the control to the right to progressively increase the fan speed. With the control at '0', the fan is stationary and the volume of air entering the passenger compartment is solely dependent upon the ram effect of the vehicle moving through the air.
Rear Air Conditioning
Discovery rear air conditioning is controlled by two-way switches. When the front air conditioning is operating, either switch can operate the rear air conditioning. A rear four position blower switch gives the rear passengers the option of variable blower rate. To enhance rear air conditioning, there are 5 air vents which may be open or closed and the direction of the air flow may be adjusted. No temperature control is provided.