horn BMW 740IL 2001 E38 Central Body Electronics ZKE Manual

• Signal "NG"; switched ground output signal provided to the GM. The signal is used for
two purposes,
1. As a momentary acknowledgment that the tilt sensor received STDWA and is cur-
rently monitoring the vehicle angle.
2. If the tilt sensor detects a change in the vehicle's angle when DWA is armed, signal
NG is switched to inform the GM to activate the siren.
When the tilt sensor receives the STDWA signal from the GM it memorizes the vehicle's
parked angle. The angle of the vehicle is monitored by the solid state electronics. Once
armed, if the angle changes, the tilt sensor provides a switched ground signal to the GM
to activate DWA.
As with the interior sensor, the tilt sensor is also switched OFF when the vehicle is locked
two times within ten seconds. The LED will flash one time for confirmation. This allows the
sensor to be switched OFF for transportation purposes.
Glass Breakage Sensors (Early E38 - before FIS Sensor): The door windows (includ-
ing the rear quarter glass wire loop) are monitored by inductive sensors mounted on the
inside of the door behind the trim panel. A closed window is recognized by a magnetic plate
on the glass lining up with the sensor.
If the glass is broken, the plate falls away and the signal from the sensor changes and the
GM will activate the alarm.
Alarm Siren: The alarm siren is mounted in the rear wheel well, behind the inner wheel
housing cover (early E38 used an alarm horn). The E53 alarm siren is located in the left side
of the engine compartment.
The siren contains electronic circuitry for producing the warn-
ing tone when the alarm is triggered. The siren also contains a
rechargeable battery that is used to power the siren when the
alarm is triggered.
The rechargeable battery will allow the siren to sound if it or the
vehicle’s battery is disconnected. The siren battery is
recharged, from the vehicle’s battery, when the alarm is not in
the armed state.
37
Central Body Electronics ZKE III
625200108.eps