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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 
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Climate Control Systems 
Minimum differential  (Red) 
Maximum  differential (Blue) 
14.7.8 Fault Code  23 
Refrigerant  Pressure Switch 
(A / C vehicles  only) 
Test the refrigerant  pressure switch and harness  continuity  between pin 17 (22-way connector)  and pin 13 (22-way 
connector) A / C CM. 
If there  are no continuity  problems, renew  the A / CCM. 
If there is no continuity,  test the continuity  of the switch  between black 2-way connector  pin 2 and  ground  (pin 1). Switch should  be closed  circuit at a pressure  of between 2 and  30 bar. If the switch  is open  circuit,  suspect  faulty switch 
or  incorrect  gas charge. 
If the switch is operating  correctly. Inspect the switch  harness for open  circuit or short circuit  to ground.  Rectify  as 
necessary. 
Nnfe: In  ambient  temperatures  below O"C, the system may  log fault  code  23 because  low ambient  can cause a tem- porary  low gas pressure.  In ambient temperatures  above 35"C, the system may  log fault  code  23 as temporary 
high  pressure  can exist  within  the system. * 
=8WZkIO% 
=2 WZf 10% 
1 4.7.9  Fault Code  24 
Differential  Potentiometer 
Test the 5 volt supply  to differential potentiometer  between pin 1 and  pin 2 (ground) at the potentiometer  connector. 
If  there  is no 5V supply,  inspect the harness  for open  circuit or short circuit  to ground. 
If no  harness  faults are apparent, 
renew the A / CCM. 
1ynf9: The A / CCM  provides  a common  5V output  and ground  to all  servos, ie all servo  potentiometers  are fed by a 5V rail. If all servos  are inoperable  check the A/ CCM outputs  and harness,  renew the A/ CCM. 
Check  resistance  between pins 1 and 
2, value should  be IOWZ +10% at 20°C. 
If the resistance  measured falls outside the  said limits,  renew the potentiometer. 
Check  resistance  between pins 1 and 3 at  both  maximum  and minimum  differential potentiometer  positions; adjusted 
via the variable differential control  thumb wheel situated  between  dash centre  face level  vents. 
Position 
Closed 
Open 
Closed 
Open 
I Differential  potentiometer  position 1 Resistance 1 
Action Value Test point 
Recirc.  lk2 
Fresh  4k8 Pin 2 ground 
Recirc.  4k8 
Pin 
1 +5volts Fresh  1 k2 
If the  resistance  measured falls outside the  said limits,  renew the potentiometer. 
a 
0 
0 
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rl E I ect r i ca I 
15.2.6 STATUS AND WARNING LAMPS 
15.2.6.1  Transmission Sport Mode (green) 
The transmission sport mode indicator is controlled  by a signal from the Transmission  Control Module (TCM). The 
indicator is illuminated  whenever 'Sport' mode is selected; a low  signal  is sent  to the instrument  pack (pin 14,48-way connector). 
15.2.6.2  Traction Control OFF (green) 
Two traction control lamps  are provided: control fail and  control off. Both  lamps  are controlled  from one input  from 
the  ABS I TC control  module. 
Under  normal operating  conditions, the input signal should  be high. 
If the input line  is continuously  low, traction con- trol has failed  and both  lamps  will illuminate. If the input signal  is a 4 Hz square wave the traction control  system is 
switched  off, therefore  the 'traction 
off lamp  will illuminate. 
15.2.6.3 
The  operation of the direction indicator  'tell-tales' is controlled  by the BPU. The 'tell-tales'  are the  only indicators on 
the instrument  pack which  can be illuminated  with the ignition OFF, for hazard  warning. 
The  signal  from the BPU  to the instrument  pack is pulsed,  switching  the direction indicators on  and 
off at the correct 
frequency.  The 'tell-tales'will illuminate when the signal is low. If the frequency  doubles, this signifies that  an exterior 
direction indicator  bulb has failed;  the bulb failure warning lamp should  also be illuminated. 
The  signal  is fed  to two  separate  inputs to the instrument  pack, on the  48
-way  connector;  pin 40 for LH directional  indi- cator 'tell-tale' and pin 41 for RH. 
!We: If both  direction indicator  'tell-tales'  are permanently illuminated; this  indicates that the BPU  has not been 
PECUS  programmed.  Check that a PECUS  label is attached  to the  BPU. 
Direction  Indicators - LH & RH (green) 
15.2.6.4  Main Beam  (blue) 
A low  signal  is supplied  to the instrument  pack (pin 24,48-way, connector)  from the BPU  when main  beam is selected. 
This illuminates the main  beam 'tell-tail' indicator lamp. 
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Electrical 
15.4.3.1 
Connectors AI and A2form the  seat internal harness interface.  Connectors B1 and B2form thecabin/seat link harness 
interface. 
Seat  Control Module  Connector Pins 
0 
I CONNECTOR B1- 12 PIN. BLUE 1 
Pin No. Description Input / Output Signal 
1  JDS 'K Line I/O Serial data bus 
2 JDS 'L' Line I/O Serial data bus 
3 Earth I/P High current 
4 Battery supply 1 I/P Supply +VE 
X300 EDM Issue 1 August 1994 15.4 - 6