Steering Column Adjustment

Power for the column adjustment motor is supplied via a megafuse in the BJB to the CJB. A fused supply from the CJB is passed to the instrument cluster which controls the power application to the motor.

The column adjust switch is hardwired to the instrument cluster. Up/down and in/out selections on the switch are each passed through a resistor of differing values to the instrument cluster. The cluster monitors the output value from the switch and operates the motor in the required direction and simultaneously energizes the required solenoid for rake or reach adjustment. When the applicable solenoid is energized, a clutch is engaged and locates on a lead screw. The motor rotates the lead screw and the rotational drive of the screw is transferred into linear movement of the applicable clutch to move either the rake or reach adjustment. For reach adjustment, the lead screw drives the outer housing in or out as required. For rake adjustment the lead screw drives a rake lever which moves the column up or down as required.

The position of the column is monitored by potentiometers which are connected to the instrument cluster. The cluster monitors the output signal from the potentiometers to precisely control the positioning of the column in each plane.

The instrument cluster controls the memory positioning of the column via a medium speed CAN bus connection to the driver's seat module. The driver's seat module receives information regarding the particular remote handset used to enter the vehicle and outputs positional information relative to that stored for the handset. This information is passed to the instrument cluster via the medium speed CAN bus which moves the column to the memorized positions.

The column logic in the instrument cluster also incorporates an entry/exit mode. When the vehicle is unlocked or the ignition is switched off, the instrument cluster lifts the column upwards to its maximum rake position to allow the driver more room below the steering wheel and improve access/egress of the vehicle. When the ignition is next switched on the column will adjust to its previous position.

The electric steering column lock is controlled by the CJB.