1998 JAGUAR X308 air outlet

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

Parts List
The air conditioning unit houses the evap orator, heater matrix and their temperatur e sensors. The unit also incorporates
two servo motor operated air distribution flaps which regulate airflow to the front and rear footwells and the quantity of
airflow through the cool air bypass (air which by-passes he ater matrix) up to the upper air distribution box (ADB).
When the footwell flap is open, air is du cted to the front and rear footwell areas via the lower air distribution duct (LADD)
and appropriate ducts. The LADD is clipped to the bottom of the air conditioning unit case an d the front foot ducts clipped
onto the outlets of the LADD.
Condensate (water) which forms on the evaporator fins is drained out of the unit case through two drains, located either
side of the unit underneath the evaporator. The liquid is routed to the vehicle exterior via flexible tubes which are located
behind the firewa ll heatshield.
Refrigeration Cycle
ItemPart NumberDescription
1—Air inlet - LH (RH opposite, not shown)
2—Servomotor - cool air bypass
3—Servomotor - footwell outlet
4—Air outlet - footwell
5—Air outlet - ADB (with foam seal)

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.

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