Cooling JAGUAR X308 1998 2.G Workshop Manual

19. Reconnect air conditioning pipes at the evaporator.
Remove blanking plugs.
Install, fully seat and lubr icate new O-ring seals.
Install bolts.
20. Install instrument pane l; refer to 76.46.01.
21. Recharge air conditioning system; refer to 82.30.30.
22. Re-fill cooling system; refer to 26.10.01 or (SC) 26.10.01.
23. Reconnect battery ground cable (IMPORTANT, see SRO
86.15.15 for further information).

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

15. Remove the temporary wooden support strut and reconnect
gas struts to the hood.
16. Check transmission fluid level an d top up as required; refer to
307A-01 (N/A) or 307B-01 (S/C), operation 44.24.02.
17. Refill the cooling system; refer to 26.10.01 or (SC) 26.10.01.
18. Recharge air conditioning system; refer to 82.30.30.
19. Reconnect battery ground cable (IMPORTANT, see SRO
86.15.15 for further information).

LO demands the maximum COOLING performance from the system with the blowers operating automatically at maximum
speed.
HI demands the maximum HEATING performance from the system with the blowers operating automatically at maximum
speed.
Pressing and holding either temperature selection button co ntinuously changes the setting temperature by steps of 1°,
every 0.4 seconds.
• NOTE: The interior temperature does not change when the temperature scale is changed between Celsius and Fahrenheit,
however the temperature display will chan ge to the nearest equivalent number.
Examples:
17C 61F 17C 66F 19C 66F
• NOTE: When operating in HI or LO mode and the AUTO butt on is pressed, the system will adopt the nearest automatic
control temperature setting:
LO AUTO DISPLAY INDICATES 17° C or 61° F HI AUTO DISPLAY INDICATES 31° C or 90° F
• NOTE: When switching the system on us ing the AUTO button, the system will display the previous temperature setting,
except under the following conditions:
LO, system OFF, auto display indicates 17° C or 61° F HI, system OFF, auto display indicates 31° C or 90° F
17. 17. Face
Pressing this button will direct all airflow to the center and side face vents only; pressing again will return the system to
automatic control mode.
• NOTE: When in AUTO mode and in a hot c limate, a bleed of cold air is delivered to foot level. This bleed automatically
shuts off when the inte rior temperature has cooled sufficiently.
18. 18. Bi-Level
This push-on / push-off button will direct air to the center and side face vent s and the front footwells. Pressing the button
(off) will return the system to automatic control mode.
19. 19. Foot
This push-on / push-off button will direct the majority of airflow to the front footwells with a small bleed of air to the fron t
and side screens. Pressing the button (off) will return the system to automatic control mode.
20. 20. Demist
Pressing this button will direct air to the front and side screens and the front foot wells. Pressing the button (off) will return
the system to automatic control mode.
Fascia Air Outlets
90
HIHI

Parts List
Air temperature from the centre (and EOD) vents is slightly cooler than the foot outlets; however this temperature cannot
be varied independently.
The EOD vents, not shown, feature similar controls.
Automatic Operation
Initial setting
Should a new A/CCM be fitted, it will 'power-up' in the OFF mode; switching ON will result in the following settings:
After initial start up the system operating conditions will be st ored in the A/CCM to the conditions which prevailed prior to
ignition OFF.
Maximum Heating / Cooling
Maximum Heating (temperature setting HI)
ItemPart NumberDescription
1—Airflow control
2—Air direction control
FeatureStatus
Setting temperature24°C or 75°F
LH and RH blower assembly recirculation / fresh flapFresh mode
Control modeAutomatic 'AUTO' displayed
BlowerAuto
Compressor outputA/C ON
Heated windshield and mirrorsOFF
Water valveAuto temperature control
ItemControlOverride Allowed
Water valveFully open (not energised)-
BlowerMaximumYes
Fresh / recircFreshYes
Air distributionFeet (state lamp OFF)Yes
A/C systemOFFYes
Cool air by-passFully closed-

Maximum Cooling (temperature setting LO)
Air Conditioning Control Module (A/CCM)
Location

The A/CCM is located on the right hand side of the air conditioning unit and controls all system functions.
The temperature within the passenger compartment is continually compared with the temperature selected on the control
panel LCD. The A/CCM receives data input signals and compares these with signal s from the system temperature sensors
and feedback devices. Based on this information the A/CCM adjusts the air outlet temperatur e, airflow and distribution from
the air conditioning system in to the passenger compartment.
Identification
ItemControlOverride Allowed
Water valveFully closed (energised)-
BlowerMaximumYes
Fresh / recircRecirculationYes
Air distributionFace (state lamp OFF)Yes
A/C systemONYes
Cool air by-passFully open-

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

The solar sensor is mounted on the top surface of the fascia between the defrost outlets.
The sensor is a photo-diode which is calibr ated to measure direct sunlight. It provides an output signal to the A/CCM which
automatically reduces air temperature an d increases fan speed (airflow volume) to compensate for solar heating.
Evaporator Sensor

This thermistor device changes electrical resistance as a result of temperature variations.
The sensor is positioned next to the evaporator fins and measures air temper ature after it has passed through the
evaporator. The sensor inputs a signal to the A/CCM which controls the compress or (see table) when the refrigeration
system is operating.
The sensor's connector is located on the LH side of the air conditioning unit, in front of the main power connector.
The A/CCM disengages the compressor clutch when the temperature of the air off the evaporator is 2° C or less. This is to
prevent the moisture which may collect between the cooling fins of the evaporator from freezing and thus restricting airflow.

Heater Matrix Temperature Sensor
Evaporator Temperature SignalCompressor State
3°CON - clutch engaged
2°COFF - clutch disengaged

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:

detectable difference in the voltage reading (due to minimal current flow); if there is a detectable difference, clean the cable terminal and the adjacent area of the body.
When the voltage has been measured, STOP THE ENGINE.
Reconnect the battery or fit a new battery if it was established that the battery was at fault (Refer to 414-01).
If the cooling fans operate during the above test, the large demand of current will overload the generator and cause the
engine to stall.
If the battery is in a low state of charge the voltage will rise momentarily when the battery is disconnected. However, the
maximum that the voltage can increase to with this new gene rator is 25V and then only for a maximum time of 200 mS.
Using a Substitute Battery
A substitute battery may be fitted for the tests. This batter y must be a known good example and must have been off-charge for at least twelve hours, with a term inal voltage of approximately 12.8V.
Ensure that all electrical loads are swit ched OFF and that the engine is cool.
Start the engine and allow to IDLE.
Measure the voltage across the battery term inals. It should have dropped a little due to the large start current and then
risen to a value of between 13V and 15V.
If the above test (whichever one used) indicates that the generator is not working then the connections on the rear face of
the generator should be checked. If there is a faulty connection, then the ge nerator will not perform correctly no matter
how fast it is driven.
Checking Generator Connections

ItemDescription
1Multi-Plug Connector
2B+ Main Output Terminal