
Power  Window  Motors: The  window  motors  are  mounted  on  the  cable  regulators.  The
window  motor  control  circuit  consists  of  two  wires  for  operating  the  motor  in  both  direc-
tions. 
The  motors  are  activated  by  relays  in  the  GM  of  door
modules  (front  doors).  The  relays  provide  either  power
or ground depending on the direction of window travel.  
The  GM  controls  the  polarity  of  the  motor  based  on  a
request  to  run  the  window  (window  switch,
Convenience Opening/ Closing). 
The windows are run to the limit stops which is detect-
ed  by  an  amperage  increase  in  the  control  circuit.
Additionally,  the  window  run  cycle  is  limited  to  a  6-8
second duration if in case the amperage increase is not
detected or there is a malfunction with the regulator. 
Window Motor Limit Stop Function: If the windows are run up and down continuously
a limit stop function is activated to prevent the window motors from overheating. The GM
monitors the number of times the window motors are activated. Each cycle is counted and
stored in memory.  
If the repetitive window activation (up/down) exceeds one minute, the GM deactivates the
internal relays and disregards any further input requests. The GM provides motor activation
after  a  short  duration  but  not  for  the  full  one  minute  monitoring  cycle.  Over  time,  the  GM
slowly reverses the stored count of activation until the stored number equals 0.
Convenience  Opening/Closing: The  GM  provides  the  convenience  open/close  feature
providing control of the power windows (and sunroof) from outside the vehicle with the key
in the driver’s door lock cylinder. The FZV provides the same function for the opening only.
• The anti-trap feature is active during convenience closing from the driver’s door lock.
• The convenience open feature provides outside activation of the windows and sunroof
in the same manner.
• If the GM receives a request to operate convenience close or open for more than 110
seconds, the function is deactivated and a fault code is stored.
• The  Car  Memory  Feature  can  activate  and  deactivate  the  Convenience  Open  Feature
from the FZV’s control.
46
Central Body Electronics ZKE III
FRONT DOOR
REGULATOR
615200114.eps 

Seat/Mirror/Steering Column Memory
Purpose of the System
The  front  seats,  outside  rearview  mirrors  and  steering  column  (if  equipped)  positions  are
electrically  adjustable.  The  “customized”  adjustment  positions  can  be  memorized  and
stored for three diferent users and recalled back to the individual positions (with the excep-
tion of the passenger seat - not in memory).
The  basic  features  of  seat/mirror/steering  column  operation,  as  well  as  the  memory  posi-
tions is integrated into the ZKE III system.
• Seat/Steering Column Memory 
Module (PM SM).
• Driver’s Door Switchblock Mod- 
ule (PM FT/SB - early E38 was  
separate).
• Passenger’s Door Module (PM  
BT - E53 combined with window  
switch).
• General Module (GM III).
• 3 Position Memory Switch.
• Seat Switch.
• Steering Column Switch.
• Seat/Steering Column/Mirror 
Motors.
The Seat/Steering Column Memory Module communicates with the DISplus or MoDiC for
diagnosis and Vehicle Memory encoding.
58
Central Body Electronics ZKE III
System Components:                               Inputs - Processing - Outputs
E38/E39 Shown 

68
Central Body Electronics ZKE III
Center  Console  Switch  Center  (SZM): From  1999  MY  E38,  E39  and  E53  vehicles  are
equipped  with  a  SZM  to  control  the  front  seat  heating  and  provide  a  diagnostic  interface
with the DISplus/MoDiC via the K BUS. 
The SZM directly controls:
• Front Seat Heating
• Rear Window Roller Blind
SZM  also  provides  a  unitized  switching  center
for:
• Park Distance Control (PDC)
• Dynamic Stability Control (DSC III)
• Electronic Damper Control (EDC). 
The switch signal output for these systems is a direct output signal. All diagnosis functions
are carried out through their respective control systems.
SZM Monitoring of Seat Heating 
Battery Voltage:The SZM switches current supply to the heating elements off when bat-
tery  voltage  drops  below  11.4  volts.  However,  the  heating  stage  LEDs  remain  on.
Regulated  output  current  resumes  when  battery  voltage  raises  above  12.2  volts  for  more
than 5 seconds.
SZM Internal Temperature: The power output stages for the seat heating elements gen-
erate a considerable amount of heat when in stage 1 operation. The SZM monitors it’s own
internal temperatures and reduces the heating output when internal temperatures rise to a
temperature  of  185
OF  or  switches  it  off  completely  above  203OF.  As  with  battery  voltage
monitoring, the heating stage LEDs remain on when these temperatures are exceeded.
Fault Monitoring:The SZM monitors the temperature sensors and heating mats for faults.
Detected faults are stored in the SZM. Fault Symptom Troubleshooting in conjunction with
stored faults will initiate the diagnostic paths using the DISplus/MoDiC. The following faults
can be recognized:   
• Shorts or opens in the wiring circuits.
• Shorts or opens in the temperature sensors.
• Open in heating element.  
If a short is detected in the temperature sensor, the seat heating is switched off to prevent
overheating. The Stage LEDs are also switched off with this fault present. 

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
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CHECK
ENGINEOIL SERVICEOIL SERVICEINSPECTIONINSPECTIONP
1/min
x1000km/hELECTRONICMPH1
2020404060608080100180160140 1201002001202201402400234
5
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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 

Review Questions
1. List the functions directly controlled by the GM III._______________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
2. How does the GM III communicate with other control modules?__________________
_________________________________________________________________________
_________________________________________________________________________
3. What effect does road speed have on the wiper system? What effect does it have on 
an AIC equipped vehicle?  Where does the road speed come from?_______________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
4. How does the GM III recognize the key position from the drivers door?____________
_________________________________________________________________________
_________________________________________________________________________
5. Describe the procedure used by the GM III to recognize an FZV key. Can the GM 
differentiate between different keys?  How many can it recognize?________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
6. What “convenience” features are available from the FZV key?____________________
_________________________________________________________________________
_________________________________________________________________________
7. Describe what happens when the GM receives the crash signal from the MRS.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
8. Why does the SHD (sunroof) module require initialization but the windows do not? 
_________________________________________________________________________
_________________________________________________________________________    
79
Central Body Electronics ZKE III