900 SE Hatchback L4-1985cc 2.0L DOHC Turbo EFI (1997)
Glass Breakage Sensor: Description and Operation
The sensor senses sound (microphone), such as a window being broken. It is integrated with the dome light in the roof (Cabriolet: adjacent to the interior
rearview mirror) and connected to the electronic control module as follows:
-
Anti-theft alarm via pin 7/signal and pin 5/ground
-
Anti-theft alarm with VSS via pin 7/signal and pin 13/ground
The separate ground input for the sensor in the anti- theft alarm without VSS has a filtering effect to avoid differences in potential between the electronic
control module's main ground and the sensor's ground input.
If a window is broken while the anti-theft alarm is armed, the sensor sends an analogue signal to the electronic control module so that the alarm will be
set off. Next to the sensor is a button for manual disconnection of the glass breakage sensor. When this button is pressed, the electronic control module
senses a change in the signal level and the sensor is disconnected.
