Join Date: Apr 2013
Location: Brisbane Australia
You are correct about the 156 having a tilt sensor, but it doesn't have "shock" sensors, it uses Volumetric Sensors in behind the centre pillar trim.
Basically the sensor measures the change of the volume of air (pressure) within the cabin. When that changes, such as the breaking of the window or a door forced open, it triggers the alarm.
This is done so that if the car is bumped, leant on, the bloody cat jumps on it, it doesn't go off every 5 seconds waking the whole neighbourhood up at 2.00am, but will go off if someone actually is trying to force their way into the car.
Patty - 2004 Alfa 156 2.0JTS Sportwagon
Ruby - 2000 Alfa 156 2.0 TS Selespeed with Sports Pack
(Eibach 2.5 Lowering Springs)
(Bilstein Sports Dampers )