Interfaces to steering-column switch cluster

The steering column switch cluster has a drop arm switch on the left and right. The right-hand steering column stalk is for operation of the functions of the wash/wipe system. The left-hand steering column stalk is for operation of the high-beam headlight or turn indicators as well as the functions of the onboard computer. A steering angle sensor is no longer installed in the steering column switch cluster. The steering angle is determined by the rotor position sensor of the electromechanical power steering (EPS). Using this signal, the Integrated Chassis Management (ICM) or the Dynamic Stability Control (DSC) calculates the actual steering angle.

NOTE: If the vehicle is equipped with the latest generation of DSC (MK100), parts of the function logic that were previously calculated in the Integrated Chassis Management (ICM) are integrated in the DSC control unit. As a result, it was possible to omit the ICM control unit, among other items.

The steering column switch cluster acquires the button signals from the steering column stalks. These signals are forwarded by the steering column switch cluster on the LIN bus to the respective control units. The steering-column switch cluster forwards the trigger signal for the drivers airbag directly to the airbag's ignition capsules.

The steering-column switch cluster evaluates the button for the steering wheel heating. The steering column switch cluster sends this signal across the LIN bus to the steering wheel module.

The following graphic shows an example of a steering column switch cluster (front).

Fig 1: Overview Of Steering-Column Switch Cluster Components

Courtesy of BMW OF NORTH AMERICA, INC.

Item	Explanation
1	Steering column switch cluster
2	6-pin plug connection: Airbag ignition squibs
3	6-pin plug connection: Horn switch, local interconnect network bus and power supply for buttons and shift paddles
4	Steering column lever, wiper switch
5	4-pin plug connection: Terminal 15N and terminal 31
6	Steering column lever, turn indicator/high-beam switch

The following graphic shows an example of a steering column switch cluster (rear side).

Fig 2: Overview Of Steering Column Switch Cluster (Rear Side) Components

Courtesy of BMW OF NORTH AMERICA, INC.

Item	Explanation
1	Steering column switch cluster
2	4-pin plug connection: steering wheel heating button and function LED
3	12-pin plug connection: Local interconnect network bus, supply and shift paddles
4	12-pin plug connection: Airbag and supply