1994 BMW 750IL sensor

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Central Body Electronics ZKE III
Rain Sensor Function
The rain sensor is online as soon as it receives KLR operating power.
• When the windshield wiper stalk switch is placed in the intermittent position the GM sig-
nals the rain sensor control module via the K-Bus of the request for intermittent wiping
and the position of the knurled wheel (sensitivity).
• As an acknowledgement, the rain sensor sends a command via the K Bus to activate the
wiper motor. If more than 12 seconds pass before the GM receives the acknowledge-
ment, the GM concludes the rain sensor has a defect and operates the intermittent wipe
function as a system not equipped with a rain sensor. The wiper intermittent cycling is
based solely on the knurled wheel setting.
• The rain sensor continuously monitors the windshield for rain accumulation and signals
the GM to activate the wipers based on the knurled wheel position and how fast the rain
accumulates on the windshield.
• The knurled wheel position signal (1-4) via the K bus informs the rain sensor of the select-
ed level of sensitivity.
- Position 1 (least sensitive) delays the wiper activation signal.
- Position 4 (most sensitive) sends the wiper activation signal to the GM sooner.
• When the wiper motor park contacts signal the GM of the wiper arm position, the signal
is simultaneously sent to the rain sensor as an indication that the windshield has been
cleared of water drops and causes the rain sensor to reset the sensitivity delay timer back
to 0.
• If night time driving is detected via the integral photocell, the sensitivity to water droplets
is increased causeing a shorter delay than day time driving.
• Depending on the intensity of the rain the wipers will be operated continuously as if set in
the normal wiper stalk switch position regardless of the knurled wheel setting. For this
reason, the vehicle speed signal on the K bus is not utilized on rain sensor equipped wiper
systems.

• If the ignition switch is turned off with the wiper switch in the intermittent position, the rain
sensor will only become active after the ignition is switched back on and one of the fol-
lowing occurs:
- The stalk switch is moved from the intermittent position and then back.
- The knurled wheel setting is adjusted.
- or the wash function is activated.
The reasoning behind this switching strategy is to have the driver make a conscious deci-
sion to activate the system themselves.
Rain Sensor Control Module Adaptation
The rain sensor control module adapts to the optics system environment as follows:
Windshield Aging:As the vehicle ages the possibility of stone chipping in the rain sensors
monitoring area may occur which will cause a loss of light in the optics system.
The control module adapts for loss of light based on the intensity of the detected infra red
light with a cleared windshield (wiper motor park signal). Therefore, the rain sensors func-
tion is not adversely affected due to windshield aging.
Dirty Windows:The rain sensor adaptation reacts less sensitively to a dirty windshield
(dirt, road salt, wax residue) after a completed wipe cycle. A dirty windshield has a film on
it that diminishes the ability of the infra red to refract into present water droplets. This caus-
es a delay in the rain sensor detection capabilities which lengthens the time intervals on an
intermittent wipe.
Windshield Wiper System Failsafe Operation
The GM provides failsafe operation of the wiper system if faults are detected with any of the
following input signals:
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Central Body Electronics ZKE III
Function Faulted Input Detected Failsafe Function
Intermittent Wipe
Short or open circuit of
the knurled wheel signalDelay value for
setting 3 used.
Intermittent wipe
with Rain SensorFaulted Rain Sensor or
K-Bus Signal corruptNormal Intermittent
wipe implemented
Wiper Motor not
Functional MovingPark contact feedback
signal takes longer than
16 secondsWiper motor control
deactivated for 3
minutes

Workshop Hints
Windshield Wiper Blade Service
To access the wiper blades for cleaning or replacement,the following is required:
• With the ignition switched on (KL15), switch the wiper stalk to the “Intermittant” wipe
mode.
• Switch the ignition off when the wiper arms are in the “upright” position.
CAUTION: Do not allow the wiper arm to spring back against the windshield, glass
breakage will occur!
Rain Sensor Equipped Vehicles
Make sure the wiper blades are in perfect condition. Only use window cleaner to clean the
windows. Dirty windows can cause the Rain Sensor control module to set a fault
due to the end limits of its adaptation abilities.
Rear Window/Wiper
The wiper arm and driveshaft are connected by
splines.
Special tool #61 1 320 is required to hold the drive
shaft in the park position prior to installing the wiper
arm on to the drive shaft.
Windshield Wiper System Diagnosis
The GM monitors the following circuits:
• Wiper Potentiometer • Wiper Motor • Terminal 30
• Double Relay • Windshield Washer Pump
Note: The wiper/washer operation will be interrupted during engine cranking. The GM pro-
vides this “unload” feature to preserve the battery voltage for the starter motor.
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Central Body Electronics ZKE III
12510117.jpg

Luggage Comparment Remote Unlock: The luggage com-
parment can be opened from inside the vehicle with the
remote release button. This feature is also functions when the
doors are locked from the central button.
The GM will disregard the remote release button input when
the luggage comparment is mechanically locked with the
Master Key (valet setting).
The GM will also disregard the release input if the vehicle
speed is > 4 MPH.
The E53 remote release button is located in the center con-
sole. This input will release the rear liftgate following the same
criteria stated above.
Crash Signalling
The Multiple Restraint System (MRS) control module provides a switched signal to the GM
in the event of an accident. This signal was previously provided by the crash sensor locat-
ed in the left front kick panel (< 9/96 MY).
The signal is an output function of the MRS control module and becomes active when MRS
determines a crash has occurred. The GM unlocks the vehicle, switches on the interior
lights and flashes the exterior lights when this signal is active.
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Central Body Electronics ZKE III
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12520124.eps
12520125.eps

Door Lock Actuators: A door lock actuator contains an electric motor and an integrated
microswitch (position switch). The rotary motor movement through the gear drive mechan-
ically moves the locking latch.
When the lock actuator is operating, the motor is powered until the position switch signals
the “locked” position. If the vehicle is locked from the exterior, the motor is powered further
and the the gear mechanism is moved beyond the locked position into the “double lock”
position. The motors must be powered (in reverse) to release the double lock. The inside
door handles will not unlock a “double locked” vehicle.
E53 Door Lock Mechanism: The E53 utilizes a door latch combined with dual actuator
motors. This type of actuator is sealed, self contained units with no replaceable parts. The
door lock actuators use hall effect sensors in place of pin contacts/microswitches to pro-
vide:
• Door lock key position (driver’s door only)
• Door open/closed status (replaces door jamb
switch).
The GM monitors the lock cylinder positions over two
wires. The signals are generated by two hall effect
sensors (Hall Sensor 1 & 2) located in the actuator.
When the key is turned, a plastic cylinder in the lock
actuator is simultaneously rotated by the lock tumbler
extension rod.
An asymmetrical shaped magnet is incorporated in the plastic cylinder, which when rotat-
ed changes the magnetic influence on the hall sensors. The presence of a magnet in close
proximity to the sensing surface of either hall sensor creates a coded input over the two
wires that the GM uses to determine the key position.
• Magnet in front of sensor, current flow through the sensor is <5 mA (0).
• Magnet rotated away from sensor, current flow through the sensor is >12 mA (1).
Hall effect sensors improve the actuators reliability since they are impervious to moisture
and there are no wear contacts.
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Central Body Electronics ZKE III
12520127 lock-4

• Key in the neutral position, both sensors are
simultaneously influenced by the magnet -
0/0.
• Key turned to the unlock position from neu-
tral, hall sensor #1 magnet segment moves
away from hall sensor - 1/0.
• Key turned to lock position from neutral, hall
sensor #2 magnet segment moves away
form hall sensor - 0/1.
There are two motors incorporated in each actuator
that provide two separate functions:
Single lock/unlock function: Also known as central
lock, this motor controls the mechanical lock mecha-
nism when the central lock button is pressed to single
lock the vehicle.
The lock mechanism is fully locked at this point but can
still be opened from the interior by pulling the appropr-
iate interior door handle twice or by pressing the cen-
tral lock button again. When single lock function is acti-
vated, the fuel filler flap actuator is not locked.
Double lock/unlock function: Also known as central
arrest, this motor is activated only when the vehicle is
locked from the exterior at the driver’s door lock with a
key or when the GM receives a lock request from the
Key-less entry system. In this case the double lock
motor is activated simultaneously with the single lock
motor.
The function of the double lock motor is to mechani-
cally offset an internal rod disabling it from unlocking
the vehicle from the interior. This prevents the doors
from being unlocked by any means except from an
unlock request at the driver’s door or via the Key-less
entry.
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Central Body Electronics ZKE III
HALL SENSOR 1
HALL SENSOR 2
PLASTIC CYLINDER
WITH ASYMMETRICAL MAGNET
(Shown in the Lock Position)
SINGLE
LOCK
MOTOR
DOUBLE
LOCK
MOTOR
ACTUATOR IN UNLOCKED POSITION
ACTUATOR IN LOCKED POSITION
WHEN IN DOUBLE LOCK AN
INTERIOR ACTUATED UNLOCK
ROD IS OFFSET PREVENTING
THE LOCK MECHANISM FROM
BEING MECHANICALLY
UNLOCKED

Door Contact Hall Sensor: Also included in the drivers door actuator is a third hall effect
sensor. This sensor signals the door open/closed status to the GM. This sensor replaces
the door jamb mechanical switch of previous systems. The rotary latch plate position acti-
vates the door contact hall sensor.
• When the door latch is closed, current flow
through the sensor is <5 mA (0).
• When the door is open, current flow through
the sensor is >12 mA (1).
The passenger side front door and both rear
door lock actuators only include this hall effect
sensor (hall sensor 3). Hall sensors 1 & 2 are
not required.
Trunk Lid Close (E38 SCA)/Tailgate and Window Latching System (E39/E53): The
tailgate/trunk lid is opened by any of the three input signals: FZV, remote button and unlock
switch pad (push - trunk lock cylinder E38).
These inputs request the rear latch
actuator control circuit to be
switched to ground (exception:
presence of road speed signal,
key on with FZV request.)
The rear latch actuator unlatches
the mechanism and signals the
GM of the open latch status. The
SCA motor rotates the striker
180
O. Feed-back signalling stops
the motor. E38 - When closing the
trunk lid the trunk latch micro-
switch signals the GM to activate
the SCA motor to pull the lid
down.
Rear window unlatching is requested by the rear window switch ground signal. This signal
initiates activation of the rear window actuator relay control circuit which activates the rear
window actuator. The actuator unlatches the mechanism opening the window. The latch
simultaneously provides an open window signal for the rear window wiper motor module
as well as an interior light on request (via the wiper module).
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Central Body Electronics ZKE III
12520131.eps
E39 Sport Wagon
Shown
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Anti-Theft (DWA) System
Purpose of the System
The DWA alarm system offers vehicle protection by monitoring the doors, hood, interior,
luggage compartment and vehicle tilting. When activated, DWA deters theft by sounding
an alarm siren for 30 seconds, flashing the low beam headlights (high beam on Xenon
equipped models) and four way flashers for 5 minutes.
The control electronics for DWA are integrated in the general module. The DWA - LED
indicator is located in the rear view mirror (E38 in the top center IHKA grille).
The system is “armed/disarmed” from the driver’s door lock cylinder, remote transmitter or
luggage compartment lock cylinder. The alarm is immediately deactivated when disarmed
with the key in the driver’s door lock cylinder (may be deactivated in Conversion) or remote
transmitter.
The GM utilizes existing components and/or circuits as part of the DWA system:
• Door latch switch/sensor contacts (door open/closed).
• Trunk lid switch contact (monitored for closed trunk).
• Trunk lock key position switch (located on the trunk lock, this switch signal prevents
DWA from activating if armed when the trunk is opened with the key).
• Hood switch (monitored for closed hood, located under the hood).
• DWA status LED (part of rear view mirror).
The additional components required are:
• Interior Sensor • DWA Siren • Tilt sensor
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Central Body Electronics ZKE III
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