Range Rover. Manual - part 287

AIR CONDITIONING

DESCRIPTION AND OPERATION

Evaporator and thermostatic expansion valve

High pressure liquid refrigerant is delivered to the
thermostatic expansion valve which is the controlling
device for the air conditioning system circuit. A severe
pressure drop occurs across the valve and as the
refrigerant flows through the evaporator it picks up
heat from the ambient air, boils and vaporizes. As this
change of state occurs, a large amount of latent heat
is absorbed. The evaporator is therefore cooled and
as a result heat is extracted from the air flowing
across the evaporator. The refrigerant leaves the
evaporator, on its way to the compressor, as a low
pressure gas.

Control system

The control system operates the refrigerant system
and the control flaps in the heater unit to control the
temperature and distribution of air in the vehicle
interior. It also outputs signals to the fresh/
recirculated air servos and the blowers to control the
volume and source of inlet air. The control system
consists of:
An Air Temperature Control (ATC) ECU.
An in-car temperature sensor.
An ambient air temperature sensor.
An evaporator temperature sensor.
A heater coolant temperature sensor.
A sunlight sensor.
A dual pressure switch.
A single pressure switch.

ATC ECU

The ATC ECU comprises an integrated ECU and
control panel, and is mounted in the centre console
below the in-car entertainment unit. The control panel
contains switches for system control inputs and a
Liquid Crystal Display (LCD) to provide system status
information. Inputs from the sensors and the control
panel switches are processed by the ECU, which then
outputs the appropriate control signals.

In addition to the air conditioning system, the ATC
ECU also controls the rear screen heater and, where
fitted, the windscreen heaters and the front seat
heaters. Each push switch on the control panel has a
LED to indicate the selections made.

After installation of a new ATC ECU, it must be
initialised using TestBook to ensure correct operation
of the air conditioning system.

AIR CONDITIONING

NEW RANGE ROVER

DESCRIPTION AND OPERATION

ATC ECU control panel

1. Windscreen heater switch
2. LH temperature switch
3. LCD
4. RH temperature switch
5. Blower switch
6. Automatic mode switch
7. Compressor (economy) switch
8. Fresh/ Recirculated air switch
9. RH front seat heater switch

10. Demist mode switch
11. Windscreen/ Side window distribution switch
12. Windscreen/ Side window and footwells

distribution switch

13. Footwells distribution switch
14. Face and footwells distribution switch
15. Face distribution switch
16. LH front seat heater switch
17. Rear screen heater switch

Windscreen heater switch. Push switch for control of
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 heaters are active.

LH temperature switch. Rocker switch that sets air
temperature target for the LH side of the vehicle
interior:

•

Temperature is increased by pressing the
upper part of the switch and decreased by
pressing the lower part of the switch.

•

A short press of the switch gives a 1

C (2

F) change of the air temperature target

and a long press gives a scrolling
movement of the air temperature target.

•

HI or LO is displayed when the system
reaches an extreme of the temperature
range.

•

Passenger side temperature cannot be set
outside the tolerance of 6

C (11

F) above

or below the temperature set on the
driver’s side.

LCD. Display that shows the following:

•

Blower speed when set manually (fan
symbol and dashed line). The longer the
dashed line, the faster the blower speed.

•

Automatic (climate control) mode activated
(AUTO legend).

•

Fault detected (handbook symbol).

•

LH and RH air temperature targets in

(

F).

•

Low external air temperature warning
(snowflake symbol). Comes on if the
ambient air temperature is approximately 3

C (37.5

F) or less, to warn of the

possibility of road ice.

•

Programmed demist function activated
(demist symbol + PROG legend).

•

Exterior air temperature in

C (

F) (EXT

legend and temperature value).
Permanently displayed while the system is
on.

AIR CONDITIONING

DESCRIPTION AND OPERATION

The temperature indications on the display can be
shown in either

C or

F. To switch between the two

scales, simultaneously press and hold the two
outermost air distribution switches (face and
windscreen/side windows demist) for approximately 4
seconds.

LCD symbols

RH temperature switch. Rocker switch that sets air
temperature target for the RH side of the vehicle
interior. Operates the same as the LH temperature
switch.

Blower switch. Rotary switch with no positive stop for
manual control of blower speeds. Rotation through
180 degrees covers complete speed range:

•

Clockwise rotation increases speed of
blowers.

•

Anti-clockwise rotation decreases speed of
blowers.

RH front seat heater switch. Push switch that operates
the RH front seat heater. Operation is independent
from the air conditioning system. The heater remains
active until the switch is pressed again. The switch
LED is illuminated while the heater is active.

Automatic mode (AUTO) switch. Push switch that
controls the on/ off selection of the automatic mode.
With the switch depressed the refrigerant system, inlet
air source, blower speed, air temperature and air
distribution are automatically controlled. When AUTO
is on:

•

The AUTO symbol is displayed.

•

The exterior air temperature is displayed.

•

The display of the blower speed and the
distribution mode ceases.

•

The ATC ECU selects fresh air and
engages the compressor. If the system
automatically switches to recirculated air or
disengages the compressor, the related
LED will not illuminate.

•

The selected air distribution LED will not
illuminate.

If an alternative distribution mode is manually
selected, the system operates in a semi-automatic
mode and:

•

The AUTO symbol extinguishes.

•

The appropriate distribution LED
illuminates.

•

The ATC ECU varies the remaining
functions to attempt to achieve/ maintain
the target air temperatures.

•

A second press of the illuminated
distribution switch returns the distribution to
automatic control.

AIR CONDITIONING

NEW RANGE ROVER

DESCRIPTION AND OPERATION

If an alternative blower speed is selected the system
will also function in a semi-automatic mode and:

•

The blower speed is displayed.

•

The ATC ECU varies the remaining
functions to attempt to achieve/ maintain
the target air temperatures.

If the target temperatures are changed:

•

The ATC ECU remains in the automatic
mode.

•

The new temperature is displayed.

If the target temperatures are changed to either HI or
LO:

•

The ATC ECU sets the blend flaps to full
hot or full cold, as applicable.

•

The AUTO symbol on the LCD
extinguishes.

•

The distribution mode is adjusted to the
most appropriate setting.

•

The blower speeds increase to maximum.

•

The inlet air source and compressor are
selected as appropriate.

Air conditioning on/off (A/C OFF) switch. Push switch
that operates the clutch of the refrigerant system
compressor.

•

The switch LED illuminates to confirm that
the compressor is off (i.e. clutch is
disengaged).

•

The inlet air source defaults to fresh air.

•

The ATC ECU operates the remaining
functions to attempt to achieve/ maintain
the target air temperatures. If the ATC ECU
is unable to achieve/ maintain the target air
temperatures, the switch LED flashes for
10 seconds to advise the driver that the
compressor needs to be switched on.

•

A second press of the A/C OFF switch
returns the compressor to automatic
control and extinguishes the LED.

Fresh/ Recirculated air switch. Push switch for manual
selection of recirculated air.

•

The switch LED illuminates when
recirculated air is selected.

•

The system defaults to compressor on.

•

A second press of the fresh/ recirculated
air switch returns the system to automatic
control and extinguishes the LED.

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