heater JAGUAR X308 1998 2.G Service Manual

With EM010 and EM012 disconnected, measure the
voltage between EM010/023 and EM012/022. 1
Is the voltatage 0 (zero) V?
Yes GO to F17
No Inspect harness / connecto rs EM010, EM012 and EM023
for corrosion, damaged / pushed back pins.
Repair as required an d reconnect plug(s).
GO to F19
F17: CHECK FOR SHORT TO B+ AT O2 SENSOR HEATER

Ignition switch to position 0 1
Remove EMS fuse F14. 2
Disconnect EM010 and EM015. 3
Using a link lead, bridge EM010/016 and EM010/022. 4
Measure the voltage between EM010/023 and
EM015/001. 5
Is the voltage 0 (zero) V?
Yes Replace EMS fuse F14 but retain link lead
GO to F18
No Inspect connectors EM010, EM015, and EM023 for
corrosion, damaged / pushed back pins or repair the
harness; reconnect plug(s).
GO to F19
F18: CHECK B+ AT O2 SENSOR HEATER CIRCUIT

Symp
tom #5
Sy
m
ptom #5


Low r
e
frigerant charge
*
Check f or 'hissi
ng' at expansion
valve; may be witnessed by low
HIGH side pressure. Recover / recharge
*
Moi
s
ture or air in the system
*
Chec k syst
em pressures
*
Heat er ci
rcuit air-lock
*
R e
fer section 303-03 for fill / bleed procedure
*
Suct ion
pipe touching bank 1 (A)
cylinder head (rubber isolator
missing)
*
Check the pi
pe cluster for correct fitti
ng
*
• NOTE: Electrical faults may be more rapidly traced using PDU
Sym
ptom
Possib
l
e Sources
Acti
o
n
Insuffi
ci
ent
heating
Coo l
ant flow valve stuck 'closed'
Coolant flow valve stuck 'open' allowing recirculation of
coolant at engine idle
*
*
Re
new v
alve
*
Motorized in-car aspirator sei zed
*R e
new aspirator
*
Coo l
air bypass damper stuck open

*
Re new,
check fault code #43

*
B l
ocked air inlet / pollen filter
*
Chec k / cl
ean / renew
*
B l
ower speed low
*
Check performance range
*
Low cool ant
level
*
Adjust as req u
ired (verify and correct
reason for loss)
*
Engine
t
hermostat faulty
*
Check engine r u
nning temperature
*
Heater water pump seized
*Chec k op
eration
*
Heater ma trix
blocked
*
Re new m
atrix
*
Heater circui t
air-lock
*
R e
fer section 303-03 for fill / bleed
procedure
*

Sym
p
tom #4
Sym
ptom #4
Sy
m
ptom
Possib
l
e Sources
Acti
o
n
No
i
sy
system
Loose or damaged compressor drive
belt
*Adjust or r
e
new
*
Loose compressor mountings
*Check f o
r damage, tighten to specification if OK
*
Compressor oil level l
ow
*
Look for evidence of l
eakag
e and rectify as required
*
Compressor internal dama ge
*Check f o
r debris, renew compressor and receiver drier
*
B l
ower motor noise
*
Re new m
otor (assuming no fan interference)
*
Excessive refrige rant charge
*Check f o
r vibration or 'thumping'
in high pressure line; may be
witnessed by high pressure on both HIGH and LOW sides.
Recover / recharge
*

Air Distribution and Filtering - Air Distri
bution and Filtering
Description an
d Operation
Air Distribution


Ou
tside air enters the plen
um via four inlets in the lower windshield panel.
If the air conditioning system is operating in FRESH mode (not recirculation mode), then air is drawn through the four
plenum apertures (and particle filters where fitted) and into the air conditioni ng unit via the blower interconnecting ducts in
the LH and RH blower assemblies. Air is c ooled and dehumidified as it passes through the evaporator and is then 'reheated'
to the required temperature as it passes through the heater matrix.
In RECIRCULATION mode, the air in the pass enger compartment is drawn into the air conditioning unit via the recirculation
air inlets on the blower assemblies.
In FRESH mode, air flows from the cabin into the trunk through a gap between the backlight and the parcel shelf. The air is
exhausted from the vehicle through extraction vent assemblies (incorporating one way flaps) whose outlets are above the
rear mufflers.
Air Flow Path

Air Distribution Modes
Bi
-level mode

I n
strument Pane
l Air Outlets

Ite
m
De
scr
iption
1Ai
r i
nlet - from RH blower (LH opposite, not shown)
2Ai
r outl
et - instrument
panel center vents
3Air ou
tlet - defog
4Ai
r outl
et - instru
ment panel LH and RH side vents
5Air outl
et - footwell
6Flap -
cool air
bypass
7Evaporator
8Matrix -

heater

Internal Components and Ai
r Fl
ow

Air Distribution and Filtering - Driver Side Blower Motor
Removal and Installation
Removal
1. Remove upper steering co lumn; refer to 57.40.02.

2. Remove driver stowage compartment.
Remove screw.
Remove compartment.

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

4. Remove cable tie.

5. Remove duct connecting blower assembly to heater / cooler
unit.
Remove screws.
Remove duct.
6. Disconnect harness connector from blower assembly.

Air Distribution and Filtering - Passenger Side Blower Motor
Removal and Installation
Removal
1. Remove instrument panel; refer to 76.46.01.

2. Remove passenger footwell duct.
Remove nut.

3. Disconnect harness connector from blower assembly.
1. Detach connector from mounting.
2. Disconnect connector.
3. Discard cable ties.

4. Remove fasteners securing duct to heater / cooler unit.
Remove screws.

5. Remove duct connecting blower to heater / cooler unit.
Remove screws.
Remove duct.
6. Remove blower assembly.

Heating and Ventilation - Heating and Ventilation
Description and Operation
Schematic Diagram

Parts List
Heater System Components
ItemPart NumberDescription
1—Heater matrix
2—Firewall
3—Non return valve
4—Water pump
5—Water valve
6—Return to engine
7—Feed from engine
8—Non return valve (heater bypass)

Parts List
The heater circuit 'scavenges' coolant from the engine cooling system by mean s of an electric water pump. The water pump
has a protection circuit to inhibit operation when the coolant temperature is <16°C; this is to prevent possible damage to
the impeller due to the presence of coolant borne ice particles. Coolant is drawn from the en gine system through the water
valve inlet port into the heater matrix. The coolant passes thro ugh the bottom section of the heater matrix from left to right
filling the end tank of the matrix before returning through the top half of the ma trix and through the outlet ports of the
water valve and back into the engine cooling system.
Non return valves are located in the heat er bypass hose and the hose between the water pump and valve. These valves are
required to prevent coolant flowing in th e wrong direction at low engine speeds and restrict convected flow through the
heater after the engine is switched off.
When the exterior ambient temperature is > 0°C the refrigerat ion system automatically operates cooling and dehumidifying
incoming air before it is re -heated by the heater matrix.
Water Valve Assembly
Location
The water valve assembly is located above the water pump, in the engine compartmen t and is secured to the firewall by a
bracket. The valve operates by means of an electrical solenoid which oscillates the valve stem between the inlet and outlet
ports.
When in automatic mode, the water valve duty cycle is influenced by the following inputs to the A/CCM:
Outlet air temperature 'Air off' heater matrix temperature External ambient Coolant temperature
ItemPart NumberDescription
1—Assembly pump - water
2—Hose - from header tank
3—Hose / connector - return to engine
4—Hose - heater feed to matrix
5—Valve - non return (by-pass)
6—Hose / connector - feed from engine
7—Hose - heater return from matrix
8—Assembly valve - water
9—Valve - non return

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