heater JAGUAR X308 1998 2.G Repair Manual

Compressor:
Features
Engine mounted, driven by the accessory drive belt. Fixed displacement type. High-pressure relief valve, to avoid system over-pressure. ECM controlled clutch energized via a relay.
Receiver drier:
Vertically mounted on the ri ght-hand side of the engine compartment next to the engine coolant radiator. Fitted with the high-side charge port. Includes a fluorescent tracer dye me chanism to aid leak detection.
ItemPart NumberDescription
1—Compressor assembly
2—Condenser
3—Evaporator and heater matrix (internal)
4—Receiver drier
5—4-level pressure switch
6—Expansion valve (internal)
7—High-side charge port
8—Low-side charge port
9—Suction muffler
10—Discharge hose
11—Discharge pipe
12—Suction hose
13—Suction pipe
14—Liquid line
15—Jumper hose (condenser hose)

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)

Air Conditioning - Evaporator Core
Removal and Installation
Removal
1. Remove heater / cooler unit; refer to 82.25.21.

2. Remove air conditioning control module from heater / cooler
unit.
Slacken upper fixing.
Remove lower fixings.

3. Remove evaporator pipe firewall seal plate.
Remove screws.
Remove plate.

4. Disconnect heater matrix temperature sensor.
Detach heater matrix temperature sensor connector from
unit.
Disconnect connector.

5. Remove footwell servo motor from heater / cooler unit.
Disconnect connector.
Remove screws.
Remove motor complete with bracket.
6. Disconnect evaporator sensor connector.

Installation



Detach heater / cooler unit connector.
Detach evaporator sensor connector.
Disconnect connector.

7. Remove heater / cooler unit upper case from lower case.
Remove screw.
Remove 15 clips.
Remove upper case from lower case.

8. Remove evaporator from case.
Remove sensor and clip.
Remove evaporator.
1. Installation is the reverse of removal.

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).

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

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

The heater matrix temperature sensor is a thermistor which changes its electrical resistance in response to changes in air
temperature converting a temperature rating to an electrical signal.
The sensor connector is located on the RH SIDE of the air conditioning unit. The sensor bead is located inside the unit down-
stream from the heater matrix and measures the 'post-heater' air temperature, before the air is distribu ted to the cabin The
sensor provides a signal to the A/CCM which adjusts the duty ratio of the water valve to provide the required air
temperature from the heater.
Ambient Temperature Sensor
The sensor is a thermistor which changes its electrical resistance in response to changes in air temperature, converting a
temperature rating to an electrical signal.

The ambient temperature sensor measures exterior air temper ature and is mounted on the crossbeam, in front of the
condenser on the LH side.

The signal from the ambient sensor allo ws the A/CCM to compensate for the ambient conditions and to display the
information on the control panel - updated every four (4) seconds.
Sensor response is 'damped' by the A/CCM and ther efore does not appear to react to temperature chan
ges as quickly as the