heating JAGUAR X308 1998 2.G User Guide

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

Heating and Ventilation - Heater Core
Removal and Installation
Removal
Installation

1.
Drain radiator coolant only; re fer to 26.10.01 or (SC) 26.10.01.
2. Remove instrument panel for access; refer to 76.46.01.

3. Remove driver footwell duct.
Remove screw.
Remove duct.

4. Disconnect cool air bypass serv o motor connector and heater
matrix pipes.
1. Disconnect connector.
• NOTE: Position suitable clot h to absorb coolant leakage
before disconnecting pipes.
2. Remove screws and retaining brackets.
3. Remove screws and matrix clamps.
• NOTE: Discard O-ring seals from pipes; fit suitable
blanking plugs.
Detach pipes from matrix.

5. Remove heater matrix from heater/cooler assembly.
1. Remove screw.
2. Remove retaining plate.
Reposition instrument panel support bracket to permit
removal of heater matrix (RHD only).
3. Remove heater matrix.
1. NOTE: Lubricate and install new O-ring seals.
Installation is the reverse of removal procedure.

Heating and Ventilation - Heater Core and Evaporator Core Housing
Removal and Installation
Removal
1. Disconnect battery ground cable (IMPORTANT, see SRO
86.15.19 for further information).
2. Recover refrigerant from air co nditioning system; refer to
82.30.30.
3. Drain radiator coolant only; refer to 26.10.01 or (SC)
26.10.01.
4. Remove instrument panel for access, refer to 76.46.01.

5. From under the hood: Disconnect air conditioning pipes at the
evaporator.
1. Remove bolts.
2. Discard O-rings.
3. Install suitable blanking plugs.

6. Disconnect heater hoses from heater matrix pipes.
1. Release spring band clips and disconnect heater hoses.
2. Install suitable blanking plugs.

7. From inside the vehicle: re move driver footwell duct.
Remove screw.
Remove duct.
8. Remove upper steering column lower fixings.
1. Remove nut.
2. Remove bolt.

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

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-

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

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

System Self-test
Control Panel Fault Code Listing • NOTE: Reference fault code #23*: In ambient temperatures below 0° C, this code may be logged because the low
ambient causes a tempor ary low gas pressure.
• NOTE: Where the ambient temperature rises above 40° C, with the engine close to overheating, electrical feed to the
compressor clutch may be cut and code #23 registered.
SymptomPossible SourcesAction
0 Normal operation no
fault codes presentNone
*Wait 30 seconds for system
self-check.
*
11 Motorized in-car
aspirator malfunctionHarness / connector fault
Sensor open / short circuit
*
*Panel fault codes are not
stored for motorized in-car
aspirator motor failure.
*
12 Ambient
temperature sensor
malfunctionHarness / connector fault
Sensor open / short circuit
*
*After rectification, disconnect
the vehicle battery for 10
seconds to reset the system.
*
13 Evaporator
temperature sensor
malfunctionHarness / connector fault
Sensor open / short circuit
*
*Refer to PDU
*
14 Water temperature
input malfunctionInstrument cl uster output
*Refer to PDU
*
15 Heater matrix
temperature sensor
malfunctionHarness / connector fault
Sensor open / short circuit
*
*Refer to PDU
*
21 Solar sensorSensor open /short circuit
*Refer to PDU
*
22 Compressor lock
signal faultLow refrigerant charge, low compressor oil level, loose drive
belt Harness / connector fault
*
*Adjust items as required
*
23 Refrigerant pressure
switch malfunctionHarness / connector fault
Switch open / short circuit
*
*Refer to PDU
*
23 Refrigerant pressure
low refrigerant charge * Leak from damaged pipe or joint
*Rectify as required and
recharge system
*
24 Face vent demand
potentiometer faultPotentiometer open / short circuit
Harness / connector fault
*
*Refer to PDU
*
31 LH fresh / recirc.
potentiometer faultHarness / connector fault
In certain circumstances the servo motor may over-travel
and cause further logged faults. This may be cured, following
fault rectification, by cycling the ignition ON-OFF-ON 3 times
*
*Refer to PDU
*
32 RH fresh / recirc.
potentiometer faultHarness / connector fault
In certain circumstances the servo motor may over-travel
and cause further logged faults. This may be cured, following
fault rectification, by cycling the ignition ON-OFF-ON 3 times
*
*Refer to PDU
*
33 Cool air by-pass
potentiometer faultHarness / connector fault
In certain circumstances the servo motor may over-travel
and cause further logged faults. This may be cured, following
fault rectification, by cycling the ignition ON-OFF-ON 3 times
*
*Refer to PDU
*
34 Defrost vent
potentiometer faultHarness / connector fault
In certain circumstances the servo motor may over-travel
and cause further logged faults. This may be cured, following
fault rectification, by cycling the ignition ON-OFF-ON 3 times
*
*Refer to PDU
*
35 Centre vent
potentiometer faultHarness / connector fault
In certain circumstances the servo motor may over-travel
and cause further logged faults. This may be cured, following
fault rectification, by cycling the ignition ON-OFF-ON 3 times
*
*Refer to PDU
*
36 Foot vent
potentiometer faultHarness / connector fault
In certain circumstances the servo motor may over-travel
and cause further logged faults. This may be cured, following
fault rectification, by cycling the ignition ON-OFF-ON 3 times
*
*Refer to PDU
*
41 LH fresh / recirc.
motor faultHarness / connector fault
Servo motor seized or sticking
Flap seized or sticking
*
*
*Refer to PDU
*
42 RH fresh / recirc.
motor faultHarness / connector fault
Servo motor seized or sticking
Flap seized or sticking
*
*
*Refer to PDU
*