
15.4.1.4 Remote Recall 
Remote activation  of memory positions 1  and 2 can be achieved  using the  key fob transmitters (one  per set of keys). 
lfthe  vehicle  is unlocked  using the  remote transmitter  the stored  driving  position  will be adopted  automatically. If the 
vehicle  is unlocked  using the remote transmitter  and an exit position  is already set  the corresponding entry position 
will  be adopted  until the ignition  key is inserted,  the stored driving position  will then  be restored. 0  ~ 
15.4.1.5 
Reverse Mirror Dip 
On selection  of reverse  gear and operation of the mirror toggle switch  downwards, the passenger side rear view  mirror 
will  automatically tilt downwards  to assist  reverse  parking.  Upward adjustment disables reverse  dip, a further down- ward adjustment when still in reverse  gear reinstates reverse dip.  The mirror  will return  to normal position  when any 
other  gear position is  selected. 
15.4.2 SYSTEM COMPONENTS 
15.4.2.1  Seats 
- Driver and Passenger 
The driver  and passenger  seat adjustment  systems comprises  the following  components: 
o Fore / aft motor 
o Front raise / lower motor 
o Rear raise / lower  motor 
0 Squab  recline motor 
0 Headrest  motor 
0 Lumbarpump 
0 Squab heater 
0 Inner cushion  heater 
0 Outer cushion  heater 
0 Heater thermostat 
0 Switch  pack 
o Seat Control Module (SCM) 
o Wiring  harness 
15.4.2.2  Motors 
The five seat  position adjustment motors  are located  below the  seat cushions  (horizontal  and vertical adjustment)  and 
behind the  squab (recline  and headrest  adjustment).  Each motor unit incorporates a potentiometer which provides 
directional movement position control  via feedbackvoltage variations  to the  SCM.  Positional  variations  are activated 
by the  SCM in response  to signals  from switches mounted  on the  seat  switch  pack. 
15.4.2.3  Lumbar Pump 
The lumbar  pump, located  behind the seat squab  allows  adjustment  of seat  rigidity  by increasing/decreasing air pres- sure in the lumbar  pad. The pump motor  is controlled  from a switch on theseat switch pack and governed by  an in-line 
pressure  switch. 
A solenoid valve  is used  to regulate  air flow  to the  lumbar  pad. 
15.4.2.4  Heaters and  Thermostats 
The two  cushion  heaters and squab  heater  are  regulated by a single in-line thermostat  and operated by a switch 
mounted  on thecenter  console switch pack. Operation  of this switch  causesthe Body Processor  Unit (BPU) to energize a timed  input to SCM  (for 11 minute f 1) which  in turn  causes  SCM to energize  the heater  supply.  The supply  will 
remain on  until timed out, although the  heater circuit will be broken by  the thermostat  if the  set temperature  is ex- ceeded. 
Note: Heatingcan only  occur when the ignition  switch is position I1 and  the ambient  temperature  is belowthe thermo- stat  pre-set value  of 26°C. 
X300 EDM 15.4 - 3 Issue 1 August 1994  

rl E I ect r ical 
15.4.6 NON-MEMORY AND MANUAL  APPLICATIONS 
15.4.6.1 
Non-Memory 
Seats,  column  and mirrors  may be supplied without memoryfacilities  on certain  vehicles. In this case,  adjustment  of 
each  application  is still controlled in the same  way but the memory  facility is disabled and  the memory  switch pack 
not  fitted. 
15.4.6.2 Manual  Seats 
Manual  seats are adjustable  vertically and horizontally, vertical adjustment  being motorized but horizontal adjustment 
manually  effected. The seats  have heated  cushions and  squab, but are not operated by an electronic  control module. 
Control  is effected  using three  relays, two for vertical adjustment  and one for heating. 
Vertical  adjustment  is requested 
by operation  of a switch  located  on the  left-hand  side of the  seat  front which  completes 
the  electrical  supply to either  the raise  or lower  relay as required.  When either relay is energized  a change  of contact 
state  connects  one side  of the motor  to 
+12V and the other side to ground.  Reverse operation  reverses supply and 
ground  connection. 
Heating is still  controlled by a timed  output  from the BPU.  Operation  of a switch  located  on the 
center console  indicates 
to  BPU  that heating  is required.  Battery  voltage is then  applied  to the  heater  relay for 11 minutes.  The  relay contact 
completes  the heater circuit,  providing seat heating  (and illuminating  the switch  surround) until the timer  expires, or 
optimum  seat temperature is  achieved. Operation  of the  heater  switch  before 'time-out' is achieved cancels  the heat- ing request.  Operation of the heater  switch  after 'time-out' has been achieved  re-starts the heating  cycle. 
15.4.6.3 Manual Column 
Manual column  adjustment in the two planes is achieved by purely  mechanical  means,  release catches  allowing col- 
umn movement within a fixed  locking  mechanism.  

Electrical rl 
Carry out the exit 1 entry mode  procedure below under the conditions  stated below: 
. Key in ignition  barrel 
. Driver's door closed 
. Auxiliary ON 
. Park brake ON 
. Gear  selector in Park. 
Exit 1 Entry  Mode 
1. 
2. 
3. 
From the  driver's seat, position  the memory  mode switch,  located  on the  LH side  of the 
steering  column, to auto. 
Operate  the seat,  column  and mirror  switches  to preferred  driving position. 
Note: 
Remove  key from  ignition.  Check that seat  moves  backwards  and column  tilts upwards 
and  away,  creating  maximum  space for exit. 
Yes:  Proceed to step 
4. 
No: 
Seat  must  be a minimum of  50mm from rear end stop. 
Abort  test and  refer  to Diagnostic  Sub
-Routines. 
4. 
5. 
3. 
Refit key in ignition, open  driver's  door. Check that seat  moves  backwards and  column tilts 
upwards  and away,  creating  maximum  space for exit. 
Yes:  Proceed to step 
5. 
No: 
Leave  key in ignition  and exit  the vehicle,  closing driver's  door.  Ensure  that column and 
seat return  to driving  position.  Re-enter vehicle and ensure  that column and seat  move  to 
entry position.  Close door and check  that seat 
/ column return  to previously  selected 
driving  positions. 
Yes:  Test complete. 
No: Refer  to Diagnostic  Sub-Routines. 
Abort 
test and  refer  to Diagnostic  Sub
-Routines. 
Seat heaters  (driver and passenger) 
1. 
2. 
Turn ignition ON and locate heater select  switch on the center console. 
Operate  the switch  to initiate  seat heating.  Does the switch surround illuminate? 
Yes:  Proceed to step 
3. 
No: 
Allow  sufficient  time for heater  to take effect.  Does seat heat  level increase  in all 
designated  areas? 
Abort 
test and refer  to Diagnostic  Sub
-Routines. 
4. 
5. 
Yes: Proceed to step 4. 
No: 
Allow time  span to exceed  12 minutes.  Does switch surround light extinguish  and heating 
cease? 
Yes:  Proceed to step 
5. 
No: 
Re-select heating,  allow cycle to commence  then operate  switch again.  Does switch 
surround  light extinguish  and heating  cease? 
Yes:  Test complete 
No: Refer  to Diagnostic  Sub-Routines. 
Abort 
test and refer  to Diagnostic  Sub
-Routines. 
Abort  test and refer  to Diagnostic  Sub
-Routines.  

rl E I ect r ical 
6A. Heating (powered seats) 
a. Examine harness wiring, checking  continuity  between SCM connector AI pins 9 and 
10. A resistance  value of 1.5-3.252 should  be recorded  indicating all heating 
elements  intact and thermostat  closed. 
Check  continuity  from BPU  black  48
-way connector B, pin 38 to center console  seat 
heater  switch module  connector pin 
5. Operate switch and check  continuity  from BPU 
black  48
-way connector  B pin 38 to  ground. 
Check  continuity  between cushion heater module  and squab  heater  module pins; 
resistance values  of 
1.0-2.052 and 0.51.252 respectively should be achieved. 
Check  continuity  from SCM connector  B2 pin 
2, through  console switch LED to ground; 
a resistance  value of 0 - 0.552 should be recorded. 
b. 
C. 
d. 
1 
J86 - 1872 
Fig. 1 Memory  Seat Heaters 
e 
0 
0 
0  

68. Heating (manual seats) 
0 a. Examine harness wiring,  checking fuse F9 in RH 'A' post base  fuse box. 
Ensure  continuity  between heater relay connector  pin 85 and  BPU  yellow  48
-way 
connector  pin 23.  Measure resistance  from heater  relay pin 87 and console  switch 
connector  pin 10. 
Check  continuity  from BPU black  48
-way connector B  pin 38 to center console  seat 
heater  switch module  connector pin 
4. Operate switch and check  continuity  from 
BPU  black  48
-way connector  pin 38 to ground. 
Check  for 
+12V supply  at seat heater  relay connector  pins 30 and  86. 
Check  continuity  between cushion  heater module  and squab  module pins; resistance 
values 
of 1.0-2.052  and 0.5-1.252 respectively  should be achieved.  Ensure secure 
ground  connection  from squab connector  pin 3. 
Check  continuity  from console  switch connector  pin 
10 through console switch  LED to 
ground; 
a resistance  value of 0-0.5Q should  be recorded. 
b. 
C. 
d. 
e. 
I' T 
I 19 15 16 
17 OK 
J86 - 1873 
Fig.  1  Manual  Seat Heaters 
Issue 1 August 1994 X300 EDM 15.4 - 25  

E I ect r ica I rl 
15.4.9.16 Key to schematic diagrams 
I 2 
I 3 
i 7 
, I 13 
14 
a1 15 
j 
20 
p 
23 
30 
Description 
Seat  control  modules  (driver and passenger side) 
RH ,'A' post  base  fuse-box 
LH 
,'A' post base fuse-box 
Head  restraint  motor and potentiometer 
Squab  recline  motor and potentiometer 
Seat  movement  motor 
- fore 1 aft - and potentiometer 
Seat  movement  motor 
- rear raise 1 lower - and potentiometer 
Seat  movement  motor 
- front raise 1 lower - and potentiometer 
Seat  raise  lower  motor  (manual  seats) 
Seat  switch  pack 
Seat  raise relay  (manual seats) 
Seat  lower  relay (manual  seats) 
Seat  raise 
/ lower  selector  switch (manual  seats) 
Lumbar  pump unit 
14.1  Pump 
14.2  Solenoid valve 
14.3  Pressure  switch 
Seat  cushion  heater 
15.1  Thermostat 
15.2  Inner cushion  element 
15.3  Outer cushion  element 
Squab  cushion  heater 
Center console switch unit 
17.1  Switch LED 
17.2  Heatina select switch 
Body  processor  unit 
Heater  relay (manual  seat) 
Column 
tilt motor  and potentiometer 
Column  reach motor  and potentiometer 
Column 
I mirror  control module 
Column  switches 
23.1  Joystick 
23.2  Passenger's  rear view mirror  up 
I down motor  and potentiometer 
Passenger's  rear view mirror  left 
I right motor  and potentiometer 
Mode switch (exit 
I entry) 
Driver's  rear view  mirror  up 
I down motor  and potentiometer 
Driver's rear  view mirror left 
1 right motor  and potentiometer 
Driver's  door switch  pack 
Mirror  polarity  select switch 
Mirror  joystick 
X300 EDM 15.4 - 35 Issue 1 August 1994