Electronic steering wheel module

The steering wheel module is integrated in the steering wheel. The steering wheel module switches the steering wheel heating on and monitors its function.

The steering wheel module controls the vibration actuator (only in vehicles with lane change warning and lane departure warning).

The steering wheel heating can be switched on using the button for the steering wheel heating in the steering column.

If the steering column switch cluster is an independent control unit, the button signals are read in by the steering column switch cluster (SZL). If the steering column switch cluster is not a control unit, the button signals are forwarded from the steering column switch cluster across the local interconnect network bus to the respective control units.

Depending on the series, the button signal from the button for the steering wheel heating is evaluated by the following component:

• steering column switch cluster (SZL), e.g. F01, F10
• Body Domain Controller (BDC), e.g. F15, G11, G12
• Junction Box Electronics (JBE), e.g. F25
• Front Electronic Module (FEM), e.g. F30

The corresponding control unit sends a request to switch the steering wheel heating on or off as a local interconnect network bus message. The steering wheel module switches the steering wheel heating on and monitors its function.

The steering wheel module keeps the surface temperature of the heating mat at approx. 36 °C via a pulse-width modulated signal (PWM signal).

The steering wheel module controls the vibration actuator. The request to activate the vibration actuator is sent to bus users by the ICM (Integrated Chassis Management) or the DSC (Dynamic Stability Control) as a bus signal via FlexRay.

• Vehicles with junction box electronics (JBE) control unit and steering-column switch cluster control unit (SZL):

  The steering-column switch cluster forwards this request across the LIN bus to the steering wheel electronics.

• Vehicles with junction box electronics (JBE) control unit without steering-column switch cluster control unit (SZL):

  The junction box electronics forward this request via the LIN bus to the steering wheel electronics in the steering-column switch cluster. The steering column switch cluster is not a control unit.

• Vehicles with control unit front electronic module (FEM) or Body Domain Controller (BDC): The front electronic module or the Body Domain Controller forwards this request via local interconnect network bus to the steering wheel module in the steering column switch cluster. The steering column switch cluster is not a control unit.