Ignition Switch: Description and Operation

IGNITION SWITCH





The ignition switch is located in the left hand end of the steering column lock assembly. The switch is held in the column lock casting with two locking tabs which engage in slots in the column lock casting.

The switch has a slot which provides for the location of the drive shaft which passes through the column lock. This shaft is rotated by the driver when the ignition key is turned in the key barrel. This rotation turns a drum inside the ignition switch which moves two electrical contacts to select the required ignition position. A spring loaded ball locates in a seat for each of the three ignition switch positions, allowing the driver to feel when the required position is reached.

On vehicles with automatic transmission. a solenoid is located on the side of the ignition switch. The solenoid, which is controlled on a single wire from the transfer box control module, prevents the key from being removed from the key barrel if the transmission selector lever is not in the PARK (P) position. The transfer box receives the transmission position status via a message transmitted from the transmission control module on the CAN bus.

The solenoid, when energized, moves a pin which prevents the ignition switch returning fully to the '0' off position. This prevents the key being removed until the transmission is in the PARK position.