Range Rover P38
80
HEATING AND VENTILATION
NEW RANGE ROVER
2
DESCRIPTION AND OPERATION
DESCRIPTION
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
initialised using TestBook to ensure correct operation
of the heating and ventilation system.