Steering column adjustment and steering wheel heating

The button for the steering column adjustment can be moved in four directions. It can be used to raise or lower the steering column or to set the distance to the driver.

The steering column switch cluster evaluates the status of the switch. The steering column switch cluster relays the status signal to the bus in the form of a message. The Body Domain Controller (BDC) evaluates the button signal from the switch for the steering column adjustment. In accordance with the request for the adjustment, the Body Domain Controller (BDC) relays the signals to the control electronics for the electrical steering column adjustment.

The electrical steering column adjustment activates the servomotor. The adjustment travel is registered by a hall effect sensor in the respective electric motor and processed in the control electronics.

The button for steering wheel heating is evaluated by the electronics of the steering-column switch cluster. The electronics in the steering column switch cluster transmit the command to the steering wheel electronics to switch the steering wheel heating on or off via the LIN bus.

The steering wheel module switches the steering wheel heating on and monitors its function. The steering wheel heating has an NTC resistor. The purpose of this resistor is to control the temperature of the steering wheel heating.

The following graphic shows the switch block for the steering column adjustment and steering wheel heating as an example F15.

Fig 1: Identifying Steering Wheel Heating Button, Switch Block And Wiring Harness Section

Courtesy of BMW OF NORTH AMERICA, INC.