Light Switch Center (LSZ)

Light Switch Center (LSZ)












The Light Switch Center is a new compact component that combines the electronic control, switching, and monitoring for all exterior lighting on the E46. In addition the LSZ controls the illumination and intensity of the instrument cluster lighting and LCD blocks. The LSZ assembly is mounted in the dash and consists of two serviceable components; the switch assembly and the control module.

The LSZ provides the functions of the LCM including:
- Hot and cold monitoring of the exterior lights.
- Emergency lighting function
- Short circuit protection
- Redundant storage of mileage and SI data

The total scope of the LSZ system includes the following:
- LSZ control module
- LSZ switch assembly
- High-low beam/turn signal switch
- Brake light switch
- Hazard warning light switch
- Fog light relay
- Exterior lights
- Dash/LCD lighting

Component Operation
The LSZ control module receives inputs from the following switches:

Headlight/parking light switch, fog light switch, potentiometer and photo-transistor mounted in the LSZ switch assembly.

- These inputs are received directly from the LSZ switch assembly.

Turn Signal/Highbeam Switch
- The turn signal and headlight (high/low) beam are resistance coded inputs over two wires to the LSZ control module. The LSZ carries out the switching function based on the voltage drop input.

Hazard Warning Switch
- The hazard switch provides a ground input to the LSZ to control the operation of the hazard warning lights.
- The hazard warning lights will be switched on in the event of an accident from the crash sensor input provided by the MRS control module.

Brake Light Switch
- The brake light switch is a hall sensor that receives power when KL R is switched on. The switch is low until the brake pedal is pressed. When the LSZ receives a high signal from the switch the brake lights are switched on.
- If the hall sensor fails, the brake lights will be switched on continuously.