9-3 Viggen Convertible (9400) L4-2.3L Turbo (B235) HO (2001)
Hood Sensor/Switch (For Alarm): Description and Operation
Bonnet switch
General
The bonnet switch is located on the rear left of the engine bay and acts as a sensor for the bonnet. The switch is connected to pin 41 on the TWICE
control module.
Function
A pulse width-modulated (approx. 3.5%) voltage is supplied continuously from the control module via a 1 Kohm pull-up in TWICE to the switch. From
this voltage, the control module can detect whether the bonnet is opened when the alarm is armed by testing the voltage at the input concerned.