1994 JAGUAR XJ6 sensor

Climate Control Systems
28-
I llSA I
1.
2.
3.
4.
5.
6.
7.
8.
9.
IO.
11. 12.
13.
14.
15.
21J 20
Instrument pack
Fascia switch pack
Defrost servo.
Air distribution box Solar sensor
Control panel
Centre console
LH blower motor
Water valve
Circulation pump
Coolant temperature sensor
LH front fuse
-box
Circulation pump relay
Ambient temperature sensor
A
/ C compressor
17
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27. 28.
29.
16 1's J86 1767
Compressor clutch relay
Trinary pressure switch
Radiator fan pressure switch
Control module
RH blower motor
Engine control module
Motorized
in-car aspirator
A
/ C isolate relay
RH blower motor high speed relay RH blower motor relay
LH blower motor high speed relay
LH blower motor relay
-
-
Fig. 1 Component Location Diagram
Issue 1 August 1994 2 X300 EDM

Climate Control Systems
System Differences
m:
Heater only vehicles do not have the following fitted:
This section applies generally to both air conditioning and heater systems. System specific descriptions, pro-
cedures, tests etc. are indicated.
0 Solar sensor
0 Clutch request and acknowledge circuitry.
0 Refrigerant pressure switch.
0 Control panel - deletion of air conditioning button.
6 cyl. engined vehicles do not have either the electrical load inhibit or the compressor lock sensor.
Heated Front Screen
(HFS) is optional on both air conditioning and heater panel versions.
14.2 COMPONENT DESCRIPTIONS
14.2.1 Control Panel
The control panel (Fig. 1) provides the operator interface with the climate control system.
The control panel communicates with the
A / CCM via a serial data communications link. During each data transfer
cycle the control panel states whether it is an air conditioning or heater version, thus enabling the A/ CCM to control
the system functions accordingly.
Tontrol panel operation is described in detail in the 'Climate Control Systems' section of the VSM.
-
Fig. 1 Control Panel (A / C with Heated front Screen)
J86 - I726
14.2.2 Control Panel Inputs /Outputs
Description I CableColor
I 1 I Output clock I Grey I
2 Output start Grey / Red
3 Input data
in Grey / Yellow
4 Output
data out Grey / Green
5 Output
ignition positive White / Red
6 Output auxiliary positive
White / Blue
7 Output
ground Black
8 Dimmer
Red
9 Dimmer override Red / Green
I 10 I Not connected I- I
I 11 I Not connected I- I
I 12 I Not connected l- I
X300 EDM 3 Issue 1 August 1994

Climate Control Systems
14.2.3 Solar Sensor (Fig. 1)
The solar sensor is mounted on top of the facia, between the
facia defrost grilles.
The sensor isconstructed around
a photo-diode to measure
direct sunlight. The sensor provides an output response sig-
nal totheA1CCM;thisensuresthe in-cartemperaturestabil- ity whilst reducing outlet temperature to compensate for
solar load heating. The solar sensor is fitted to aircondition- ing vehicles only.
14.2.4 Engine Speed Signal
The A 1 CCM receives an engine speed signal from the En- gine Control Module (ECM).
This signal facilitates compressor lock sensing (12 cyl. ve- hicles only).
This signal also aids the A
1 CCM inhibition of the heated
screen relays. At engine speeds lower than 800 RPM the A I CCM assumes poor idle or engine not running and will not
permit the selection of the heated screens.
14.2.5 Ambient Temperature Sensor (Fig. 2)
The ambient temperature sensor is located within the LH
brake cooling duct.
The sensor detects exterior airtemperature and provides the
A
I CCM with a signal to allow compensation for ambient
conditions.
The A
1 CCM is then capable of informing the control panel of the ambient air temperature in both Centigrade and
Fahrenheit, and updates the information every four
seconds.
The sensor is damped and
so does not detect temperature
fluctuations as quickly as other temperature sensors. This
facility prevents temporary temperature fluctuations affec
- ting overall temperature control.
14.2.6 Vehicle Speed Signal
The A 1 CCM receives a road speed signal from the instru- ment pack, derived from the ABS 1 TC CM.
This signal is required to control the blower fan speed to mi
- nimise the effects of ram air, i.e. blower fan speed changes
in proportion to vehicle road speed.
The signal also determines the frequency
at which the ambi- ent air temperature is updated. The road speed compensa-
tion for blower control is inhibited when the selected
temperature is 'LO (maximum cooling) and 'HI' (maximum
heating) and defrost mode.
14.2.7 Evaporator Temperature Sensor
Located next to the evaporator fins, the sensor detects the air temperature leaving the evaporator, and sends this sig- nal to the A 1 CCM.
When the temperature approaches
OOC, the A 1 CCM disen-
gages the compressor to prevent freezing conditions. When
thetemperature rises above3OC.theAlCCM re-engagesthe
compressor.
J82-L06 Fig. 1
Fig. 2
0
0
Issue 1 August 1994 4 X300 EDM

Climate Control Systems
14.2.8 Heater Matrix Temperature Sensor
This sensor is positioned inside the air conditioning unit just
downstream of the heater matrix. The sensor monitors the
post
-heater air temperature, before the air is distributed to
the passenger compartment. In conjunction with the A / CCM this sensor provides the input to maintain a constant
outlet temperature.
14.2.9 Coolant Temperature Signal
This input is required to provide blower inhibit control, to
avoid cold
air being delivered in heating mode when the en- gine coolant temperature is below 3OOC. The input also
monitors the temperature of the coolant delivered to the
heater matrix to assist outlet temperature control.
14.2. IO Compressor ON Signal
This signal line monitors the compressor relay to inform the
A/ CCM of the compressor status and to facilitate lock detec-
tion and error sensing.
14.2.11 Motorized In-car Aspirator (Fig. 1)
The Motorized In-car Aspirator (MIA) detects the air tem- perature within the passenger compartment. A small motor
driven fan (blown aspirator) draws air across the thermistor,
which changes its electrical resistances in response to
changes in air temperature, converting
a temperature rating
into an electrical signal.
The MIA is located on the back of the driver's side knee
bolster.
14.2.12 Compressor Lock Signal - 12 cy/. vehicles only
This signal provides the A / CCM with compressor rotation
speed. This is then compared with engine rotation speed.
If the ratio of the compressor speed against engine speed
drops belowthe A/CCM limits, indicating compressor/ belt
slippage, the compressor clutch is disengaged.
When compressor clutch disengaging commences the A/C
LED on the control panel will flash once per second.
14.2.13 Refrigerant Pressure Switch (A/C Vehicles only)
The refrigerant pressure switch (Fig. 2) is located under the
hood on the liquid line.
The switch contacts open when abnormal pressures are
sensed. This action inhibits the compressor clutch drive.
14.2.14 Water Valve
The water valve is used in conjunction with the water pump
to regulate the output air temperature. The water valve is off when the ignition is on, engine not running.
14.2.15 Water Pump
The water pump is energized in all engine running modes
except for under cold coolant condition at blower inhibit and
in panel
off mode. The water pump is off when the ignition
is on, engine not running.
If
J82-488
KI Fia. 1 I
Fia. 2
X300 EDM 5 Issue 1 August 1994

Climate Control Systems
0
0
14.3 CLIMATE CONTROL MODULE CONNECTIONS
Fig. 1 Control Module Connector Pins
J80-098
IGN, activated high
0 Io(22-way) Input Diagnostic L-Line
11 (22-way) Input Water pump motor current Current detection resistance 7mQ
12 (22-way) Output Ignition (+VE) to control panel
13 (22
-way) System Ground
14 (22
-way) Output Ground to control panel
15 (22
-way) Output Air con isolation relay Activated when IGN ON and for 30 sec-
16 (22-way) Input Vehicle speed input
17 (22
-way) Input Pressure switch Ground for normal pressure.
IGN+ for abnormal pressure
18 (22
-way) Output Aspirator motor (In+ar sensor) 0.05A at 12V, activated high during ON
mode only
19 (22
-way) Input Sensor ground
20 (22
-way)
21 (22
-way) Output Diagnostic K-Line
onds after IGN OFF
Logic ground for diagnostic lines
X300 EDM 7 Issue 1 August 1994

Climate Control Systems
Climate Control Module Connections, continued
35 (16-way) Input Solar sensor
36 (16
-way) Input Centre vent servo motor feedback po- tentiometer
37
(16-way) Input RH air intake servo motor feedback po- tentiometer F / R
38 (16-way) Not used
39 (16
-way) Input Cool air bypass servo motor feedback
potentiometer
I 40(16-way) llnput I Coolant temperature signal
1 41 (16-way) llnput I RH blower motor voltage feedback
I 42 (16-way) I Output I RH blower motor drive signal
I 43(16-way) I Input
I Differential potentiometer
44 (16
-way) Input Defrost servo motor feedback poten-
tiometer
45
(%-way) Input LH air intake servo motor feedback po- tentiometer - F / R
46 (16-way) Not used
47 (16
-way) Input Foot servo motor feedback potentiome-
ter
48 (16
-way) Not used
49 (16
-way) Input LH blower motor voltage feedback
50 (16
-way) Output LH blower motor drive signal
51 (26
-way) Input Compressor ON signal
52 (26
-way) Output Water valve
53 (26
-way) Output RH Blower motor relay
54 (26
-way) Output Heated front screen relays
55 (26
-way) Output Heated Door Mirror relay
Specification
Open collector R = 578, connected to
IGN, activated low
Open collector
R = IKn, connected to
IG N, activated high
Open collector R = IKQ, connected to
IGN, activated high
Voltage /temperature values
Voltage
/ temperature values
Open collector
R = IKQ, connected to
IGN, activated high
AJ16
- Ground (lock sensor not fitted)
VI2 - Ign. voltage (lock sensor fitted)
Voltage
/ temperature values
Voltage
/ temperature values
Voltage
/ temperature values
Resistance 6W.
&IO%
0% closed - IV, 100% open - 4V
Resistance 6Kn
+IO%.
0% closed - IV, IOW0 open - 4V
Pulse
width modulated signal I
OV to 3V max. I
Resistance IOW. &IO%.
Min. IV, Max. 4V
Resistance
6W. +IO%.
0% closed - IV, IOW0 open - 4V
Resistance 6W.
+IO%.
Resistance 6W. &IO%.
0% closed - IV, 10096 open - 4V
I
Battery voltage when compressor ON
1 amp at 12 volts
Load
36Q at 12V IGN, activated low
0
0
0
0
Issue 1 August 1994 8 X300 EDM

Climate Control Systems
14.7.2 Fault Code 12
Ambient Temperature Sensor
0 Sensor, harness or A 1 CCM open circuit.
0 Sensor, harness or A 1 CCM short circuit to ground.
If the signal on pin 27 (12-way connector, AI CCM) remains at less than 1 volt, suspect either a short circuit to ground
on the signal wire or an open circuit on the 5 volt supply to the sensor. If the signal on pin 27 rises to approximately 5 volts, suspect an open circuit on the earth supply to the sensor.
Checkthe voltage, against the graph below (Fig. I), measured between pin 27 (12-way connector) and pin 19 (22-way
connector) A 1 C CM.
If the voltage is within the set limits, the system is operating correctly.
A resistance check can be carried out on the sensor and should conform with the figures below, measured between
pin 27 (12-way connector) and pin 19 (22-way connector) AI CCM.
10°C 3.1
- 3.7 w1 25°C 1.6- 1.8 w1 50°C 0.5 - 0.7 w1
If the resistance is outside the set limits, renew the sensor.
Nnfe:
Inspect sensor harness for open circuit or short circuit to ground. Rectify as necessary.
If the voltage is outside the set limits, renew the AI CCM.
The resistance
should continue to decrease as the temperature increases and vice versa.
80
70
80
50
40
30
OC 20
10
0
-10
- 20
- 30
- 40
V
Fin. 1
J86 -17'38
0
0
0
0
Issue 1 August 1994 14 X300 EDM

Climate Control Systems
14.7.3 Faultcode 13
Evaporator Temperature Sensor
0 Sensor, harness or A / CCM open circuit.
0 Sensor, harness or A/ CCM short circuit to ground.
This sensor monitors the temperature of the evaporator matrix, the output is used to trigger the compressor circuit
via the
A/ CCM pin 34 (12-way connector).
If the signal on pin 34 (12-way connector) remains at less than 1 volt, suspect either a short circuit to ground on the
signal wire or an open circuit on the 5 volt supply to the sensor. If the signal on pin 34 rises to approximately 5 volts
then suspect an open circuit on the sensor ground.
Checkthe voltage, against the graph below (Fig. I), measured between pin 34 (12-way connector) and pin 19 (22-way
connector) A / C CM.
If the voltage is within the set limits, the system is operating correctly.
A resistance check can be carried out on the sensor and should conform with the figures below, measured between
pin 34 (12
-way connector) and pin 19 (22-way connector) A / C CM.
0°C
4.6- 5.1 WZ
15°C 2.1 - 2.6 WZ
If the resistance is outside the set limits, renew the sensor.
Note:
Inspect sensor harness for open circuit or short circuit to ground. Rectify as necessary.
If the voltage is outside the set limits, renew the
A/ CCM.
The resistance should continue to decrease as the temperature increases and vice versa.
*C
J86-1769
Fig. 1
X300 EDM 15 Issue 1 August 1994