E53 Door Lock Mechanism: Notes
The E53 utilizes a door latch combined with dual actuator motors. This type of actuator is sealed, self contained units with no replaceable parts. The door lock actuators use hall effect sensors in place of pin contacts/microswitches to provide:
- Door lock key position (driver's door only)
- Door open/closed status (replaces door jamb switch).
The GM monitors the lock cylinder positions over two wires. The signals are generated by two hall effect sensors (Hall Sensor 1 & 2) located in the actuator.
When the key is turned, a plastic cylinder in the lock actuator is simultaneously rotated by the lock tumbler extension rod.
An asymmetrical shaped magnet is incorporated in the plastic cylinder, which when rotated changes the magnetic influence on the hall sensors. The presence of a magnet in close proximity to the sensing surface of either hall sensor creates a coded input over the two wires that the GM uses to determine the key position.
- Magnet in front of sensor, current flow through the sensor is <5 mA (0).
- Magnet rotated away from sensor, current flow through the sensor is >12 mA (1).
Hall effect sensors improve the actuators reliability since they are impervious to moisture and there are no wear contacts.
- Key in the neutral position, both sensors are simultaneously influenced by the magnet -0/0.
- Key turned to the unlock position from neutral, hall sensor 1 magnet segment moves away from hall sensor -1/0.
- Key turned to lock position from neutral, hall sensor 2 magnet segment moves away form hall sensor - 0/1.
There are two motors incorporated in each actuator that provide two separate functions: