Function

Sequence of functions for unlocking car at driver's door
The electrical switch (SN1) in the lock is operated when the key in the lock cylinder is turned in the "open" direction. This switch then conducts a negative voltage along its control line to the pneumatic system equipment.

The pneumatic system equipment (A37, A37/1) operates and generates a pressure which flows along a system of lines to all the pneumatic actuators. The diaphragms in the actuators are pressed up, operate the locks via linkages and unlock them. The fuel filler flap actuator unlocks the flap directly.

A pressure switch switches off the supply pump if a pressure of about 450 mbar is reached in the system.

The pneumatic line system and the actuators are now depressurized again by the pneumatic system equipment (A37, A37/1) - the system is depressurized and the unlocking process is complete.

The locking process proceeds in a similar way to the unlocking process. However, when the key is turned clockwise, a second electrical switch (SN2) in the lock is operated. This switch also conducts ground along its control line to the pneumatic system equipment (A37, A37/1). The direction of rotation of the pump motor is reversed and it thus generates the vacuum required for locking.







Function diagram