Hmm, perhaps this a EU option. Our XC70 had it, there was a button in the center console to
disable it so you could leave a pet in the car while the car is locked and the alarm active.
We also had an inclination sensor and glass break sensors in the boot. The interior motion sensor
is the only one that can bes tested easily, so I tried that. If the car has this sensor and the horn
of the car sounds if someone enters the car, a main part of the alarm function is still active while
the siren module is removed.
For some reason, I can't upload attachments now. The schematic drawing of the burglar alarm
shows a CAN-bus connection between the UEM (Upper Control Module) and the SCM (Siren Control
Module). The UEM als controls the sunroof. If a faulty siren module compromises the communication
in this CAN-bus branche, it may also compromise the functioning of the UEM. That is the reason that
disconnecting the siren module can (possibly) make the sunroof to work again.