1994 JAGUAR XJ6 climate control system

Climate Control Systems
14.1 WORKING PRACTICES
14.1.1 General
o Be aware of, and comply with all health and safety requirements, whether they be legislative or common sense.
This applies to conditions set both for the operator and workshop.
o Before commencing any repair or service procedure, disconnect the vehicle battery ground connection and
protect the vehicle where appropriate, from dirt or damage.
0 Work in a well ventilated, clean and tidy area (Fig. 1).
0 Keep all components and tools clean.
0 Recovery / Recycle and Recharge equipment must comply with, or exceed the standard detailed in the
preliminary pages.
Fig.
1
14.1.2 Handling Refrigerant
0 Wear eye protection at all times. Use gloves, keep skin that may come into contact with HFC 134A covered.
Should refrigerant come into contact with your eyes or skin; wash the affected area with cool water and seek
medical advice, do not attempt to treat yourself.
o Avoid breathing refrigerant vapour, it may cause ir- ritation to your respiratory system.
0 Never use high pressure compressed air to flush out
a system. Under certain circumstances HFC 134A +
compressed air + a source of combustion (welding
and brazing operations in the vicinity), may result in
an explosion and the release
of potentiallytoxiccom-
pounds.
0 HFC 134A and CFC 12 must never come into contact
with each other (Fig. 21, they will form an inseparable
mixture which can only be disposed of by inciner
-
ation.
0 Do not vent refrigerant directly to atmosphere, al- ways use Jaguar approved recovery equipment. Re-
member, HFC 134A is costly but recycleable.
continued
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Climate Control Systems
0 Because HFC 134A is fully recycleable it may be 'cleaned' by the recovery equipment and re-used following
removal from a system.
0 Leak tests should only be carried out with an electronic analyzer which is dedicated to HFC 134A. Never use a CFC 12 analyzer or naked flame type.
0 Do not attempt to 'guess' the amount of refrigerant in a system, always recover and recharge with the correct
charge weight. In this context do not depress the charge or discharge port valves to check for the presence of
refrigerant.
14.1.3 Handling Lubricating Oil
0 Avoid breathing lubricant mist, it may cause irritation to your respiratory system.
0 Always decant fresh oil from a sealed container and do not leave oil exposed to the atmosphere for any reason
other than to fill or empty a system. PAG oil is very hygroscopic (absorbs water) and will rapidly become con-
taminated by atmospheric moisture.
PAG oil is
NOTcompatible with previously used mineral based oils and must NEVER be mixed (Fig. 1). Do not
re
-use oil when it has been separated from refrigerant, following a recovery cycle. Dispose of used oil safely.
14.1.4 System Maintenance
0 When depressurizing a system do not vent
refrigerant directlyto atmosphere, always use Jaguar
approved recovery equipment.
0 Always decant compressor oil from a sealed con- tainer and do not leave oil exposed to the atmosphere
for any reason other than to fill or empty
a system.
PAG oil is very hygroscopic and will rapidly become
contaminated by atmospheric moisture.
0 Plug pipes and units immediately after disconnection
and only unplug immediately priorto connection. Do
not leave the system open to atmosphere.
0 It is not necessary to renew the receiver drier when- ever the system has been 'opened' as previously ad-
vised - see note this page. However,if a unit or part
of the system is left open for more than five minutes,
it may be advisable to renew the receiver drier. This
guidance is based on
U.K average humidity levels;
therefore, locations with lower humidity will be less
critical to moisturecontamination of the unit.
It must
be stressed that there is not
a 'safe' period for workto
be carried out in: ALWAYS plug pipes and units im-
mediately after disconnection and only remove plugs
immediately prior to connection.
J82-387
Fin. 1
U: The receiver / drier MUST be renewed if the compressor has failed or if it is suspected that debris may be in
the system.
0 If replacement parts are supplied without transit plugs and seals DO NOT use the parts. Return them to your
supplier.
0 Diagnostic equipment for pressure, mass and volume should be calibrated regularly and certified by a third
party organization.
0 Use extreme care when handling and securing aluminium fittings, always use a backing spanner and take
special care when handling the evaporator.
0 Use only the correct or recommended tools for the job and apply the manufacturer's torque specifications.
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Climate Control Systems
CL /MATE CONTROL SYSTEM 0 14*2 14.2.1 Description
The climate control system in the 1995 model year saloon has a centre mounted heater / cooler unit with separate
blower assemblies, one LH and one RH. Heating temperature control is effected by means of a coolant flow valve and
circulation pump.
For models fitted with air conditioning, cooling is provide by passing air through the evaporator, which is situated im
- mediately behind the heater / cooler case inlet ducts.
Electric motors with integral potentiometers are used to position
all flaps.
W: There are no vacuum operated components in the system.
14.2.2 Features
o Self diagnostic control system with error codes.
0 Actuator 'self check'.
0 Display element check.
m: These features will be helpful for initial trouble shooting and where Jaguar Diagnostic Equipment (JDE) is not
available.
0 'Soft touch' logic controls. 0
0 Serial link from panel to control module (NCCM).
0 LCD display for temperature, status and fan speed.
0 Variable fan speed, whether in automatic or manual mode.
0 Manual air flow distribution over-rides.
0 Compensated air flow with regard to vehicle speed.
0 Rear footwell outlets.
0 Rear face outlets.
0 Scavenge system closed circuit temperature control.
0 Heated front screen (where fitted).
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Climate Control Systems
14.3 CLIMATECONTROL PANEL
12 13 14 15 16
Fig. 1 Control layout (see key listing below)
The following description of the various control panel functions is provided as a brief over
-view to assist in function
checking. Further information concerning the control panel to component interface may be found in the fault finding
procedures (this section) or the Electronic Diagnostic Manual (EDM).
Iynfe: The system may be activated by any one of four commands. a) AUTO button item 1 1; b) DEFROST button item 12; c) NC button item 10; d) OFF switch item 1.
1. Combined push for OFF and rotary FAN SPEED control. The speed of the two fans is changed by clockwise (to
increase) or anti-clockwise rotation of the knob. Operation of the control, (push) OFF or (rotate) FAN over-rides
the AUTO selection and cancels the 'AUTO' display.
2. RECIRCULATE AIR push-on / push-off button and state lamp, used to prevent outside air being drawn into the
cabin. There are two modes:
a) Press and immediate release; provides timed recirculation of five
(5) minutes. b) Press and hold for two (2) seconds; 'latches' the mode until operator over-ride.
3. Temperature scale SELECTOR for Celsius or Fahrenheit.
4. FANS SPEED display bar graph.
5. TEMPERATURE numeric display for demand and exterior.
6. Selected temperature SCALE temperature numeric display.
7. EXTERIOR temperature option display.
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Climate Control Systems
8. AUTO selection display.
9. EXTERIOR temperature selection button. There are two modes:
a) Press and immediate release; provides timed display of four (4) seconds.
b) Press and hold for two (2) seconds; 'latches' the mode until operator over-ride.
10. A/C push-on / push-off button will either engage or disengage (as indicated by the state lamp) the refrigeration
system compressor. The state lamp is also used as a compressor speed fault indicator,see System protection, this
section.
11. AUTO push-on button and state lamp. When selected and the state lamp lit, the A/C mode is selected and control
of demand temperature, fans speed, and air distribution is automatic. AUTO is cancelled by selection of any 'dis- tribution' button, A/C off, or manual FANS SPEED.
12. DEFROST push
-on / push-off button and state lamp. When engaged, air is distributed to the screen at maximum
fans speed and the heated front screen elements (where fitted) are ener ized. The heated front screen is automati- cally timed for a six (6) minute cycle but may be cancelled by pressing tfe HEATED FRONT SCREEN button. Auto- matic temperature control is retained and the fans speed may be manually reduced. Deselection will return the
system to the previous state and selection of AUTO will resume automatic system control.
13. The push
-on / push-off (F) button with state lamp manually controls the HEATED FRONT SCREEN (where fitted).
This facility allows rapid screen de-icing using laminated electrical heating elements to supplement the hot air
defrost.
14. The push-on / push-off (R) button with state lamp manually controls the HEATED REAR SCREEN and door mirror
glass heating elements for a timed cycle of; screen twenty (20) minutes and mirrors eleven (1 1) minutes.
m: The state lamp will remain lit after the mirror timer has gone through its 11 minute cycle and will not go out
until either completion of the 20 minute screen cycle or manual override.
15. TEMPERATURE decrease button
in IoC or I0F steps.
16. TEMPERATURE increase button in
IoC or I0F steps.
w: Automatic temperature control operates over the range 17OC to 31OC (61OF to 90OF). Extreme limits selected
by items 15 and 16 ('Lo' and 'Hi') provide maximum cooling or heating at maximum fans speed.
17. FACE level manual distribution over
-ride push-on / push-off button and state lamp.
0 18. Bi LEVEL (foot and face) manual distribution over-ride push-on / push-off button and state lamp.
19. FOOT level manual distribution over
-ride push-on / push-off button and state lamp.
20. DEMIST (screen and foot) level manual distribution over
-ride push-on / push-off button and state lamp.
!Y&Q: Selection of AUTO will over-ride any manual setting and deselection of any manual distribution will revertthe
system to AUTO distribution.
21. FACE VENTTEMPERATURE CONTROL thumb
-wheel. Situated between dash centre face level vents to reduce face
air outlet temperature relative to that of the foot-well.
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Climate Control Systems
14.4 TEMPERATURE CONTROL
14.4.1 Coolant Circuit
The main coolant system supplies liquid at engine temperature to the heater matrix to provide heat to the vehicle
interior. Unlike previous air blend / constant matrix temperature systems, in-car temperature is now controlled by
mixing recirculated coolant in the heater circuit with engine-temperature coolant. Matrix temperature is controlled
by a valve which opens to raise temperature (admit engine coolant) and closes to reduce it (recirculates coolant within
the circuit). The coolant flow valve operates on a six (6) second 'duty cycle', during which it may be open for whatever
period thecontrol system dictates. FACEvent airtemperature of howeveriscontrolled bythe'cool air by-passdamper'
which allows incoming air to flow around the top of the the heater matrix and thus remain unheated.
Because the engine coolant pump is driven proportionally to engine speed, the coolant delivery rate changes with
engine revolutions thus causing temperature variations. To stabilize the flow through the matrix, and thus the
temperature, an electrically driven circulation pump has been introduced into the system.
1
1. Engine 2. Coolant flow valve 3. Circulation pump
4. Heater matrix
5. Bottom hose
6. Engine cooling system radiator
Fig.
1 Coolant circuit, schematic view
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Climate Control Systems
Manual Inputs
Automatic inputs
outputs
14.5 AIR CONDITIONING CONTROL MODULE (A/CCM)
14.5.1 Description
Theclimate control system peripheralscommunicate with theA/CCMvia three main devicecategories, plusthevehicle
power supply and ground connections.
Control panel Face Vent Temperature Control
Temperature and solar sensors
Flap
servo motor potentiometers
Circulation pump
& coolant flow valve
Power
transistor(fan speed control)
Compressor lock sensor
(12 cylinder only)
Instrument pack (coolant temp
& road speed) (engine revolutions via engine control module)
Blower motors (Left
& Right) & associated relays
Flap
servo motors
Heated front
/ rear screens & exterior mirror relays
Motorized in
-car aspirator
Compressor clutch request to engine control module (not
heater-only cars)
Circulation pump relay
Coolant flow valve
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Climate Control Systems
. Centre vent flap
Foot flap
Defrost flap
I I
14.5.2 Control Module Interfaces
. Recirculation switch
. Air con onloff switch
. System onloff switch
. Auto. / Man. select
. Set temperature
. Air flow outlet mode set
. Heated front screen switch
. Heated rear screen &
. External temp. display
. FahrenheiVCentigrade
heated mirror switch
switch
switches
. Solar sensor
. Motorized in-car aspirator
. Ambient temp. sensor
9 Evaporator temp. sensor
. Heater matrix temp. sensor
. Compressor lock sensor
. Face differential temp. control
. Refrigerant pressure switch
. Engine speed signal
. Engine coolant temperature
Vehicle speed signal
Circulation pump
. Coolant flow valve
. Power transistor (fan speed
= Servo motor potentiometers:
signal
control)
LH air inlet flap
RH air inlet flap
Centre vent flap
Foot flap
Defrost flap
Air by
-pass flap
CONTROL PANEL
4
-
4
4
4
4
4
4
A 1 CCM
e I . External temp. display
. Coolant recirculation valve
. Coolant recirculation pump
Cool air by-pass
Air Flow Speed Control
. LH blower motor & power transistor
. RH blower motor & power transistor
. LH high speed relay
. RH high speed relay
. LH air inlet
. RH air inlet
. Compressor
- . Front screen heater (to EMS)
- . Heated rear screen
and door mirrors
Fig.
1 Schematic view AI CCM Inputs & Outputs
0
0
0
0
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