1998 BMW 528i Ignition relay

Windshield Wiping/Washing
Purpose of the System
The windshield wiping/washing functions are controlled by the GM III when the ignition is
in position KL R or KL15. The system has four wiping stages and four interval wiping
speeds. The wiper motor output control is through two relays (double relay >98 MY, except
E38) that are located in the Electonics box (E box).
The Windshield Wiping System can also be supplemented with the Rain Sensor system as
optional equipment. The Rain Sensor detects rain drops on the windshield and automati-
cally activates the wipers when the stalk switch is in the intermittent position.
System Components
Wiper Stalk Switch Input:The wiping stage inputs are coded signals through a two wire
link with a combination of high/low inputs. The wiping stages include:
Single (S): Momentarily holding the wiper
switch down in the single position provides a
momentary ground signal to activate a single
sweep in slow speed.
Slow (I) and Fast (II): The stage I and stage II
wiping speeds are road speed dependent.
Stage I switches to intermittent when the vehi-
cle is stopped and stage II switches to stage I
when stopped.
Windshield Washing: The wash request provides a switched ground input to the GM by
pulling the stalk rearward. The GM activates the windshield washer pump directly.
Intermittent (Int): The intermittent wiping time inputs are provided by a potentiometer
mounted in the wiper stalk switch (1 through 4). The intermittent wiping intervals are also
dependent on the road speed. As road speed increases, the wiping interval is shortened.
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Blocking Protection = Return
Contact Signal must be
present every 16 seconds
or motor will be deactivated >98 MY
1.49v-3.5v
Headlight Washing (if equipped):When the headlights are on, the headlight washer
pump is activated with the first activation of the windshield washer pump. It is only activat-
ed again after five succesive windshield washer cycles during the same ignition key on cycle
(rest function). The GM recognises headlights on via K-Bus signalling. The GM provides a
ground on the headlight washer relay control circuit providing pump operation. The head-
light washer pump is located on the side of the washer fluid reservoir.
System Components: Inputs - Processing - Outputs
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E53 Shown

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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All window operations signals are digital inputs to the door module and GM III.
• Comfort closing/opening of the windows from the driver’s lock cylinder. The remote key
provides opening only.
• When the ignition key is in accessory or “on” position press the switch to open or close
the windows. Window operation is possible with the ignition switched off until a front
door is opened or 16 minutes (maximum) has elapsed.
• Window load switching is through relays. The front window control relays are located in
the door modules, the rear window relays are in the GM III. The GM III monitors the cur-
rent draw for end limit position. The maximum run time for the window motors is limit-
ed to 6 seconds in the one-touch mode. This allows the motors to be switched off if the
end limit load sensing fails.
E53 Style Window Switches:The E53 power window switch design is a push - pull type
switch. Each switch provides the GM with the coded ground signaling strategy as previous
two wire switches.
Pushing a switch to the first detent and holding
provides
a single ground signal on one wire
requesting the GM to operate the window
motor in the down direction.
When released, the ground signal is removed
and the window motor stops.
Momentarily pushing the switch to the second
detent and releasing provides
an additional
ground signal on the second wire requesting
the “one touch mode”, operating the window
motor automatically.
The motor runs the window down until it reach-
es the end stop.
The switch functions in the same manner for
the upward run of the window motor but the
ground signal sequencing is reversed.
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General Functions of ZKE III
Consumer Cut Off
The Consumer Cut Off function interrupts battery voltage to circuits preventing inadvertent
battery drain if one of these consumers were to remain activated. Circuits controlled by
consumer cut off will be switched off as the GM enters into the sleep mode.
For example, the interior lights are connected to the consumer cut out circuit (KL 30) and
can remain on if one of the control switches are left on. The consumer cut off will deacti-
vate KL 30 to the interior lighting after 16 minutes (or with the DISplus/MoDIC).
The following circuits are con-
trolled by consumer cut off:
• Map/Reading Lights
• Glove Box/Luggage Compart-
ment Lights
• Transmission Range Indicator
Light
• Overload Protection Relay for
- Power Seat Motors
- Steering Column Motors
Overload Protection
The seat and steering column motors receive
operating power through the consumer cutoff/
overload protection relay module. The consumer
cutoff signal from the GM signals the relay to
maintain operating power to the consumers.
If the relay module detects an increase in amper-
age (overload) the relay will open. The relay mod-
ule (K-72) is located in the electrical carrier
behind the glove box. The relay is reset by
switching the ignition “off” for 16 minutes, dis-
connecting the relay or the DISplus/ MoDIC.
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E38 Shown
Overload
Protection Relay
Module