1998 JAGUAR X308 engine

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

Inputs / Outputs
1.1. Engine speed:
Input to the A/CCM from the ECM. Heated windshield and backli ght will be inhibited when engine speed < 50 RPM.
2. 2. Vehicle speed:
Input from the instru ment cluster. Blower speed control to minimise the effects of ram ai r. Road speed compensation is inhibited when maximum
cooling LO, or maximum heating HI, is selected; also inhi bited in defrost mode with airflow set to maximum.
Used to determine the frequency at which the exterior temperature display is updated.
3. 3. Coolant temperature (signal derived from ECM via instrument cluster):
Input from the heater matrix temperature sensor used to control water valve and thus vent temperatures. Used to monitor the temperature of coolant at the heater matrix to assist the control of air outlet temperature. Used to inhibit the blowers when heating is selected and the engine coolant temperature is below 30°C. Is used to provide progressive increase in blower speed up to 60°C. To inhibit the water valve and pump when the coolant temperature is = < 10°C
Sensors and Controls
Solar Sensor

other sensors. This feature prevents the effects of sudden changes in air outlet temperatures due to factors such as:
Recirculating air from the engine cooling pack at low vehicle speeds Sudden changes in ambient temperature The effects of water splash
Motorised In-car Aspirator.

An intake grille (mounted on the fascia , outboard of the steering column and below the EOD vent) houses the aspirator
thermister. The remotely mounted motor / fan assembly draws ca bin air through the grille and thus over the thermistor; a
flexible hose connects both components.
The electrical resistance of the thermistor changes in response to variations in air temperatur e, this change being converted
into an electrical signal. The A/CCM uses this signal to adjust the temperature, airflow and air distribution from the air
conditioning unit.
Coolant Temperature Signal.
This signal is supplied to the A/CCM from the instrument cluster, the input being required to:
Provide blower inhibit control , to avoid the system in heat ing mode delivering cold air when the coolant temperature is below 35°C unless DEFROST is selected. To progressively increase the fan speed up to maximum blower speed during warm up control. To assist in the control of the outlet temperature. To avoid possible pump or valve damage ca used by ice particles in the coolant.
Compressor ON Signal.
This signal monitors the compressor relay to confirm the compressor operating state and so provide relevant fault
information.
Servo Motor Control.
Flap position, which directs the flow of air through the system, is controlled by servo motors; these may be driven in either
a clockwise or anti-clockwise direction by signals from the A/ CCM. Motor, thus flap position, is monitored via a feedback
potentiometer which is situated within the motor housing.
Servo motors control the following flaps:

RH and LH Air Intake (Fresh / Recirc) Center Vent Defrost Foot Cool Air Bypass
Blower Motor Control.
The A/CCM controls the speed of two blower motors which deliver airflow to the air conditioning unit. The blower motors are
regulated by power transistor modules which pr ovide a linear variation of blower speed.
Filter Compensation
Where particle filters are fitted as 'after market' items the A/CCM program must be changed to allow higher AUTO blower
speeds; this compensates for the slight loss of air flow. Access to the program is by PDU.
Vehicles with filters fitted OEM will have this facility enabled by Jaguars Cars Ltd.
Relationship Manual Contro l Blower Speed / Voltage
• NOTE: Blower motors are inhibited when the engine coolant temperature is below 35°C and heating is demanded, unless
DEFROST / DEMIST is selected.


Blower ModeDisplay Output - No of BarsBlower Motor Voltage (V)
OFFNil0.0
Manual LO14.00
24.33
Manual M124.67
35.00
Manual M235.33
45.67
46.00
Manual M346.33
56.67
Manual M457.00
67.33
67.67
Manual M568.00
78.33
78.67
Manual M679.00
89.33
89.67
Manual M7810.00
910.33
Manual M8910.67
1011.00
Manual M91011.33
1111.67
Manual HI and DEFROST1112.00

Connector Pin Identity Chart for FC043

Control Panel Communication
The control panel provides operator interface with the climate control system.
Control panel operation is described in detail in the D section.
Control Panel Inputs (I/P) / Outputs (O/P)
Pin NumberCircuitCircuit Function
001Ignition positive supply
002Battery isolate supply
003Auxiliary ground
004Auxiliary ground to control panel
005Battery supply
006Engine speed input
007Electrical load drive inhibit
008+5V sensors
009Clutch request to ECM
010Diagnostic L-line
011Not used
012Ignition (positive) to control panel
013System ground
014Ground to control panel
015Air conditioning isolation relay
016Vehicle speed
017Pressure switch
018Aspirator motor (In-car sensor)
019Sensor ground
020Logic ground for diagnostic lines
021Diagnostic K-line
022Not used
Pin NumberCircuitCircuit Function
1Input CLOCK
2Input START
3Input DATA IN
4Output DATA OUT
5Input ignition (positive)
6Input auxiliary (negative)
7Ground
8Dimmer
9Dimmer override
10Not used
11Not used
12Not used