1998 JAGUAR X308 speed

Engine speed (valve closed with the engine not running) Demand (set) temperature In-car temperature sensor Solar sensor
Re-heating of the refrigerated air is contro lled by the time that the water valve is open (i.e. not energised) over a six secon d
interval. The duty cycle of the water valve, the time open / time closed, is controlled by the A/CCM.
Maximum heating demand will cause the water valve to be fu lly open (not energised) to allow maximum coolant flow
through the heater matrix.
At Maximum cooling, the water va lve will be fully closed (energised) to prevent hot (engine temperature) coolant entering
the heater circuit; the pump however will continue to circulate coolant through both the heater matrix and water valve
bypass.
The water valve defaults open when the ignition is OFF.
Under engine stall conditions, when ignition is ON, the water valve will be open.
Water Pump Assembly
Located in the same area as the water valve, the water pump continually circulates coolant through the heater matrix
except when the conditions below apply:
The engine coolant is below 16°C. The ignition is OFF. Under engine stall conditions, when ignition is ON. Control panel OFF
Non return valves
The heater bypass hose has a non-return valve, located between the engine feed and return hoses. The valve prevents the
water pump from recirculating coolant fro m the heater at low engine speeds.
The flow indicator arrow embossed on the valve bo dy MUST point towards the coolant header tank.
CAUTION: Coolant flow will be compromi sed if either valve is fitted incorrectly. Observe the correct direction.
A second non-return valve is located betw een the water pump and water valve. This valve prevents hot coolant from flowing
into the heater with the engine switched off. The flow indicator arrow MUST point towards the water pump.
Heater feed and return hoses
The heater feed and return hoses are connected to the engine feed and return hoses by 'Quick-Fit' connection unions. The
feed hose has a Norma R20 connector and the return hose a Norma push and seal connector. The coolant system bleed
joints have Cobra clamps. All remaining hose connections have spring band hose clamps.
The engine feed hose is connected to the engine bypass hous ing and the engine return hose is connected to the engine
water pump.
Clamp Identification

Air Conditioning - Air Conditioning
Description and Operation
Introduction

Parts List
The climate control system features fully automatic control of temperature, blower speed (airflow) and air distribution to
maintain optimum comfort under most driving conditions.
Manual controls are provided to allow the operator to over-ride automatic operation.
System Features
ItemPart NumberDescription
1—Fascia panel with integral ducting
2—Heater / cooler assembly
3—A/CCM
4—Blower LH and RH
5—Plenum
6—Control panel
7—Solar sensor
8—Assembly valve - water
9—Assembly pump - water
10—Temperature sensor - external
11—Compressor
12—Pressure switch - 4 level
13—Motorized in-car aspirator (LHD shown)
14—Receiver drier
15—Condenser

Twin blower assemblies Center mounted evaporator, heater and air distribution unit Electric solenoid water valve controlled heating Electric water pump assembly Servo motor driven air distribution flaps Dedicated side glass defrost / demist vents External temperature sensor Motorised in-car aspirator Solar sensor
Electronic Control Panel
Liquid Crystal Display (LCD) Digital temperature display Manual fan speed level External temperature display Celsius / Fahrenheit selection Heated windshield switch (where fitted) Heated backlight switch Defrost switch Manual airflow distribution overrides (4) Access to self diagnostic system and error codes
Sensors
External ambient temperature sensor Motorized in-car aspirator Heater matrix temperature sensor Evaporator temperature sensor Solar sensor
These sensors feedback information to the Air Conditioning Control Module (A/CCM) which automatically adjusts air
temperature, airflow volume and distributi on from the air conditioning unit to maintain a stable passenger compartment
average temperature under changing weather conditions.
Major Components

Condenser:
Multi-pass fin-over-tube type, mounted in front of the engine cooling pack and directly to the radiator.
Pressure (Bitron) switch:
Located in the discharge pipe. Provides a signal, via the A/CCM, to th e ECM, to disengage the compressor clut ch should the refrigerant pressure be
< 2 bar or > 30 bar.
Provides a hard-wired signal to the ECM, to switch the cool ing fans to HIGH speed at 22 bar rising pressure and to
LOW speed at 17,5 bar falling pressure.
Provides a hard-wired signal to the ECM, to switch the radiator cooling fans to LOW speed at 12 bar rising pressure
and to switch the fans OFF at 8 bar falling pressure.
Expansion Valve

Parts List
The expansion valve is located inside the heater / air conditioning unit and comprises of a diaphragm, connected by a
capillary tube to a temperat ure sensing bulb, which regulates the valve according to temperature variations at the
evaporator outlet pipe. This component is NOT serviceable. See 'Refrigeration Cycle'
Air Conditioning (Heater / Cooler) Unit
ItemPart NumberDescription
1—Valve body
2—Pressure spring
3—Diaphragm
4—Capillary tube
5—Temperature sensing bulb
6—Valve inlet
7—Valve outlet
8—Equalizer pipe

Control Components - Control Components
Description and Operation
System Controls
The climate control system is controlled by : 1. 1. Manual input from the operator, via the center console located control panel.
2. 2. Automatically by means of the A/CCM.
Output is based upon input from the following devices:
Motorized In-car aspirator External air temperature sensor Coolant temperature sensor Heater 'air-off' (the temperature of the air leaving the matrix fins) temperature sensor Evaporator 'air-off' (the temperature of the air leaving the evaporator fins) temperature sensor Solar sensor Left hand blower recirculation / fresh air flap potentiometer Right hand blower recirculation / fresh air flap potentiometer Upper air distribution box (ADB) center and side face flap servomotor potentiometer ADB defrost flap servomotor potentiometer Air conditioning unit Foot flap servomotor potentiometer Air conditioning unit Cool Air Bypass flap servomotor potentiometer Thumbwheel controls on the facia vent assemblies which provide manu al adjustment of the airflow volume. Road and engine speed signals input to the A/CCM
Climate Control Panel
Communication between the control panel and the A/CCM is via a serial data communications link.

Switching the Climate Control system ON
The climate control system can be switched ON by pressing one of the following :
Ref #1 On / Off (resumes the system on in the previous settings).
Ref #10 A / C (resumes the system on in the previous settings).
Ref #11 AUTO (resumes the system on at the previous temperature setting).

Ref #12 DEF (resumes the system on at the previous temperature setting).
Button (switch) logic
All buttons with an integral LED state lamp conform to the following operating logic.
When the state lamp is lit the relevant func tion is operational. From this condition, pressing the button will de-activate the
function, confirmed by the LED being de-energized and the pres ence of a single audible 'beep'. A single 'beep' will
accompany the state lamp to confirm function re-selection.
1. 1. ON / OFF and manual fan speed.
Pressing this knob activates the system ON at the last settin g or switches the system OFF. Rotate the knob clockwise to
increase and anti-clockwise to decrease fan speed and thus airflow.
With the system OFF, ram air is available by the selected air di stribution mode (indicated by state lamp). Air flow will NOT
occur unless a manual air distribution mo de is selected, this air being unconditioned and flow dependent upon vehicle
speed.
• NOTE: The blowers are inhibited until the engine coolant te mperature is > 35°C, unless DEFROST, FACE or DEMIST modes
are selected.
2. 2. Manual Air Recirculation
Closes the outside air intakes of the blower asse mblies and recirculates air within the vehicle.
Two options of control are available :
Timed Recirculation. Pressing the button for less than 1.5 seconds lights up the LED (confirmed by a single bleep).
This provides recirculation of interior air for a period of approximately 5 minutes. Pressing the button within five
minutes returns the system to fresh air intake mode.
Continuous Recirculation. Pressing and holding the button for more than 1.5 seconds lights up the LED (confirmed by two beeps). This provides continuous reci rculation of interior air. Pressing the button returns the system to fresh air
intake mode.
• NOTE: Avoid using manual air recirculatio n for prolonged periods in cold weather, this may result in interior misting of
glass.
3. 3. Temperature Scale Selection
Press the appropriate button to display temperatures in degrees Celsius or Fahrenheit.
4. 4. Manual Fan Speed
Rotating the fan speed control knob (to vary fan speed) will di splay a proportional number of horizontal bars on the LCD.
There are total of eleven manual fan speeds available.
5. 5. Temperature Display
Indicator of internal demand temperatur e or external ambient temperature. The external ambient is updated every 4
seconds when the road speed > 25 km / h.
6. 6. Scale
Selected temperature scale, Celsius or Fahrenheit.
7. 7. External temperature
Symbol indicates when this option is selected

8.8. Automatic
Symbol indicates when the control of , temperature, fan speed and air distribution are all in Auto mode.
9. 9. External
There are two modes of external ambient temperature selection;
Quick Display. Pressing the button for <1.5 seconds (con firmed by a single bleep) will display the external
temperature for 4 seconds.
Continuous Display. Pressing and holding the button fo r >1.5 seconds (confirmed by two beeps) displays the
external ambient temperature continuously, the value of which will be updated every 4 seconds given that vehicle
road speed is > 25 km/h. Pressing the button again fo r <1.5 seconds resets to the previous display.
• NOTE: Continuous external temperature display will be cancel led when the ignition is switched OFF but not during engine
cranking.
10. 10. A/C
This push-on / push-off button will either select or deselect (as indicated by the state lamp) the refrigeration system.
The refrigeration system is automatically engaged when the Auto button is pressed.
• NOTE: Interior misting of screens may be reduced by continuous operation of th e refrigeration system.
11. 11. Auto
When selected and the state lamp lit, A/C mode will be operat ional and control of vent outlet temperature, fans speed and
air distribution will be automatic.
AUTO mode will disengage should manual air distribution or defrost buttons be operated or the manual fan speed knob be
rotated.
• NOTE: Automatic temperature control is constantly main tained irrespective of selected manual overrides.
12. 12. Defrost
Push-on push-off button, which when engaged will direct all air to the front and side glass at maximum fan speed. The
heated windshield (if fitted) will also be energized for a timed cycle of 6,5 minute s, but may be cancelled by pressing the
HEATED WINDSHIELD (F) button. Pressing 'DEF' again will retu rn to the last setting with automatic temperature control
being maintained.
Directing warm and humid air onto a cold screen can produce interior misting of screens. Operating the climate control
system without the refrigerati on system operating will exacerbate this problem.
• NOTE: Directing cold air onto the screen in warm humid conditions can produce external condensation.
13. 13. Heated Windshield (F)
Pressing the heated windshield button (whe re fitted) will energize the electrically heated windshield elements for a timed
cycle of 6,5 minutes; pressing the button again will cancel the request. Should the engine stall or the ignition be turned
OFF, the timer will be cleare d and the function cancelled.
• NOTE: The heated windshield may be activated with the cl imate control system OFF but the engine must be running.
In very cold ambient temperatures, icing of the interior of the glass is possible when the climate control system is operating
in AUTO mode; to reduce this poss ibility the A/CCM provides automatic operation of the heated windshield.
With the following conditions met, the heated windshield will automatically energize but the state lamp will NOT be lit.

External temperature < -10 °C Vehicle speed > 65 km / h The first two conditions exist > 2 minutes. Engine speed > 50 revs / min
14. 14. Heated Backlight (R)
Pressing the heated backlight button will simultaneously energize the heater elements for timed cycles of;
21 minutes backlight 11 minutes exterior mirrors
Pressing the button again within the 21 minute timer will cancel the request.
If the engine is stalled, or the ignition switched OFF, the backlight and door mirror timers will be cleared, resulting in both
functions being switched off.
• NOTE: Both the backlight and door mirrors may be activated with the climate control system OFF, but the engine must be
running.
15. 15. Temperature Decrease
Pressing this button (BLUE symbol) decreases the interior temperature setting in 1° increments. Should the button be
pressed when the setting temperature is below the lower automatic control temperature limit, the display will indicate 'LO'.
16. 16. Temperature Increase
Pressing this button (RED symbol) will raise the temperature setting in 1° increments Should the button be pressed when
the setting temperature is above the upper automatic control temperature limit, the display will indicate 'HI'.
Automatic Temperature Control Range
°C°F
LOLO
1761
62
1863
64
1965
66
2067
68
2169
70
2271
72
2373
74
2475
76
2577
78
2679
80
2781
82
2883
84
2985
86
3087
88
3189