ECU BMW X5 2002 E53 Central Body Electronics Workshop Manual

ALARM SIREN
The siren is located in the vehicle cowl
on the driver’s side of the vehicle. This
location provides a secure position with
loud acoustic output.
The siren contains electronic circuitry
for producing the warning 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 dis-connected. The siren battery is recharged,
from the vehicle’s battery when DWA is not in the armed state.
The siren has four wires connecting it to the system; KL 30, KL 31,
Signal STDWA (arm/disarm signal from GM), and Signal NG (acti-
vate siren output signal to the GM)
The arm/disarm output signal from the GM (STDWA) is provided to the Tilt sensor, FIS sen-
sor and the siren simultaneously. The arm/disarm signal is a switched ground that signals
the components of DWA armed/disarmed status.
The activate siren signal (NG) is high whether DWA is armed or disarmed. If a monitored
input activates the alarm, the high signal to the siren is switched to a 50% duty cycle at
the GM. The control circuitry in the siren activates the siren driver. If the DWA is armed
and the battery is disconnected the siren recognizes the normally high “NG” signal as sud-
denly going low, the siren is also activated.
SIREN INSTALLATION
POSITION
ZKE - 50