SZL: Steering Column Switch Cluster

The SZL control unit forwards the signals from the turn-signal/main-beam switch to the adaptive headlights control unit.

> E60, E61, E63, E64

1. The steering column switch cluster forwards the signals for the turn-signal/main-beam switch to the light module (LM).
   NOTE: The steering column switch cluster on the E90 has its own SI Technology bulletin (SBT). 

   This enclosure describes the steering column switch cluster (SZL) on the 5-Series.

   The contents are valid accordingly for the E65 and E66.

   The steering column switch cluster on the E90 has its own SI Technology bulletin: SI Technology (SBT) 61 07 04 (103) "E90 - Steering Column Switch Cluster"

   The SZL (steering column switch cluster) processes all data from the multi-function steering wheel. The SZL transmits the data (via the byteflight data bus) to the safety and gateway module (SGM).

   The safety and gateway module (SGM) connects the multi-function steering wheel with other systems in the vehicle. The SGM transmits the data from the multi-function steering wheel, e.g. to the following control units: wiper module, rain-light sensor, EGS, DME, KOMBI and LM.

   For reasons of safety, there are 2 additional direct wire connections to the bus:

   • from the SZL to the LM (light module)
   • from the SZL to the AL control unit: If option 217 "Active steering" is fitted, the 2nd direct wire goes from the SZL to the AL (active steering) control unit:

     This makes sure that the signal from the steering-angle sensor also reaches the AL control unit in the event of a bus error.

   Installation Location  The SZL is located on the steering column.

   How it works  The steering column switch cluster has the following range of functions:

   • SZL as control unit for the passive safety system (ASE - Advanced Safety Electronics) with connection to the byteflight data bus.
   • SZL as switch cluster for steering wheel and steering column:
     • Multi-function buttons in the multi-function steering wheel.
     • Steering wheel heating via button on left-hand side of steering column.
     • Fully electric steering wheel adjustment via button on left-hand side of steering column.
   • SZL as switch cluster for the 3 steering-column stalks.
     • Wipers
     • Turn signals
     • Cruise control system
   • SZL with steering angle sensor

   Signal path on E60, E61, E63, E64, E65, E66 up to 03/2005

   1. SZL -> byteflight  -> SGM -> K-CAN -> LM -> AHL

      (steering column switch cluster -> byteflight  -> safety and gateway module -> K-CAN -> light module -> AHL control unit)

   2. > Signal path on E60, E61, E63, E64, E65, E66 from 03/2005
      
      SZL -> byteflight  -> SGM -> K-CAN -> LM

      (steering column switch cluster -> byteflight  -> safety and gateway module -> K-CAN -> light module)

> E90

1. The steering column switch cluster forwards the signals from the turn-signal/main-beam switch to the footwell module (FRM).

For more information, please refer to SI Technology (SBT) s61 07 04 103 "Steering Column Switch Cluster".