Page 7 of 80

7
Central Body Electronics ZKE III
Power Distribution
The power distribution box for the
E38  is  incorporated  in  the  Electr-
onics  box  in  the  engine  compart-
ment. 
The power distribution box for the
E39 and E53 is inside the vehicle. 
The  main  fuse  box  is  located
inside  the  glove  box  above  a
hinged panel. 
A  “pull  out”  fuse  designation  card
is also located in the fusebox. This
notes:
• Fuse value in amps
• Location
• Circuit listing by fuse
The placement of the power distribution box is
close  to  the  main  electronics  carrier behind
the  glove  box.  The  modules/relays  located  in
the electronics carrier include (examples):
• General Module III (GM III)
• Drive away protection (EWS II)
• Anti-lock Brake (ABS/ASC+T)
• Light Check Module (LCM) - behind right kick
panel
• Overload protection relay module
An  auxiliary  fuse  block  is  located in  the  trunk
above  the  battery.  In  addition  to  fuses,  the
auxiliary fuse block also contains relays (exam-
ples):
• Fuel filler flap lock motor relay
• Fuel pump relay (some vehicles)
• Rear defroster relay
• Unloader relay 
FUSE
DESIGNATION
CARDFUSE BOX DROPS
DOWN AFTER TURNING
TWO THUMB SCREWS
12520103.eps
12510104.jpg125101106.jpg 
     
        
        Page 69 of 80

Rear Window Roller Sunblind Operation
The roller sunblind is activated by momentarily pressing and releasing (one touch) the sun-
blind rocker switch in the SZM. The SZM activates the motor in the appropriate direction.
The SZM switches the motor off when the motor amperage increases indicating the blind
has reached the end of its intended travel.
Fault Monitoring: The SZM continually monitors the motor drive amperage loads to deter-
mine jamming or blockages. If current values exceed preset values, the motor is switched
off immediately.
Faults are stored in the SZM for opens or shorts in the motor or motor’s wiring circuit. The
SZM also provides diagnostic requests to monitor the switch input status via the DISplus/
MoDiC.
69
Central Body Electronics ZKE III
KL 31 (GROUND)KL 31 (GROUND)
DIS
DIS
BMWDIS
B
M
WD
I
S
BMWDIS
BMW
DIS
D
ia
g
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o
s
e
-
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d
In
fo
r
m
a
ti
o
n
S
y
s
t
e
mDIS &
MoDiCDIS &
MoDiC
M
o
Di
C
0½
CHECK
ENGINE
CHECK
ENGINEOIL SERVICEOIL SERVICEINSPECTIONINSPECTIONP
1/min
x1000km/hELECTRONICMPH1
2020404060608080100180160140 1201002001202201402400234
5
6
7!!ABS20 DIGIT READOUT20 DIGIT READOUT
123456
prnd432
m
prnd432
m
122.4 +72.0 fo
+72.0 fomiles0
10
15 20 40
KL 30 (BATTERY)KL 30 (BATTERY)-+
KL 15 (IGNITION ON)KL 15 (IGNITION ON)
KLR (ACC)KLR (ACC)
KL 87 (OPERATING POWER)KL 87 (OPERATING POWER)
58G (PANEL LIGHTING)58G (PANEL LIGHTING)
LCM IIILCM III
PDC
EDC
DSC
MREAR WINDOW
ROLLER
BLINDSREAR WINDOW
ROLLER
BLINDS
DRIVER’S SEAT HEATINGDRIVER’S SEAT HEATING
PASSENGER’S SEAT HEATINGPASSENGER’S SEAT HEATING
K BUSK BUS
PDC CONTROL
MODULEPDC CONTROL
MODULE
EDC CONTROL
MODULEEDC CONTROL
MODULE
SZMSZM
DSC III
CONTROL
MODULEDSC III
CONTROL
MODULE
ACTIVE SEAT
CONTROL
MODULESACTIVE SEAT
CONTROL
MODULES
System Components:   Inputs - Processing - Outputs 
     
        
        Page 74 of 80

Principle of Operation
Control logic (example E38) includes:
• Servotronic control electronics active with KL R being switched "ON" - ensure  no delay
in operation if engine is started and vehicle is immediately driven.
• Plausibility  check  for  speed  signal  -  the  control  electronics  monitor  both  the  Speed  sig-
nal "A" from the  IKE and the vehicle speed signal on the K-Bus.
• The ability to detect both acceleration and deceleration from the two speed signals - the
speed signal from the IKE is updated every two seconds.
• The servotronic assist is reduced gradually when the vehicle is under acceleration.
• The servotronic assist is adopted to the lower direct reading during decel or braking.
Electric/electronic failures with the servotronic system will result in the following:
• Power/electronic  failure  of  the  control  module  or  solenoid  -  steering  assist  the  same  as
high speed driving (increased effort).
• Vehicle speed signal missing - control module retains the assist mode in effect when the
speed signal was lost.
• Speed signal implausible - steering assist the same as high speed driving (increased  
effort).
The GM also provides the diagnostic “gateway” to the Servotronic status and Component
Activation via the DISplus/MoDiC.
74
Central Body Electronics ZKE III