1998 JAGUAR X308 cooling

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

Location of J1962 socket
The J1962 socket is located at the driver side inboard footwell.
Fuse Box Details

Engine Compartment Fuse Box
2—Power Steering Link
3—Engine
4—Front Axle
5—Engine Management
6—Console
7—Seat
8—Cabin
9—Rear Electric Seat Link (optional)
10—Trunk
11—Rear Axle
12—ICE
13—Fascia
14—Forward
Fuse NoRating (amps)Circuit
110Transmission control module.
25Screen heaters relay, alternator regulator.
310Security sounder, headlamp levelling, ignition coils +Ve, fog lamp switches.
45ABS control module.
510Adaptive damping, starter relay coil, engine management control module and relays.
610Right-hand low beam headlamp.
730Power wash pump.
810Left-hand low beam headlamp.
910Security sounder.
10-Not used.
1110Right-hand horn.
1230Radiator cooling fans series/right-hand fast.
1310Left-hand horn
1430Cooling fans left-hand fast.
1510Air conditioning coolant pump.
1630ABS pump control.
1715Front fog lamps.
1830ABS pump motor.
1910Right-hand high beam headlamp.
20-Not used.
2110Left-hand high beam headlamp.
2230Wiper motor.

Engine Management Fuse Box

Heelboard Fuse Box - Right hand side
Fuse NoRating
(amps)Circuit
120Adaptive damping
215Intercooler water pump (Supercharger)
325Starter solenoid.
45Engine control module.
510Fuel injectors.
65Transmission control module
7-Not used.
810Air conditioning compressor clutch.
930Throttle motor.
105Engine control module, Park/Neutr al switch, cruise control VSV 1 and 2 (where fitted), EGR valves.
11-Not used.
1210Air flowmeter, VVT solenoids.
13-Not used.
1410HO2S sensor heaters (where fitted ), EVAP valve, ignition coils relay, throttle motor relay, AC
compressor clutch relay, radi ator fans control module, CCV.
1530Windscreen left-hand heater.
165Control module compartment cooling fan.
1730Windscreen right-hand heater.
1810Ignition coils, ignition amplifier.
Fuse NoRating (amps)Circuit
120Left-hand seat control module.
215Door lock relay, door locking actuators.
315Body processor module.
410Door mirror heaters, mirror foldback.
55Radio telephone.
610Air conditioning.
720Body processor module (column motor power).
85Rear window switchpack, passenger door switchpack.
95Passenger seat switchpack.