Horn Switch (41)

Horn Switch (41)

Main task
Used to control the horn. CIM sends the switch status on the bus.

Type
Single pin switch integrated in the driver's airbag. The switch is connected to the Sentronic circuit on automatic cars.

Connection
The steering wheel buttons are resistive multiplexing and are divided into 2 circuits: Sentronic/horn in one circuit and the other buttons in the other. All buttons are jointly grounded from CIM. The lead for Sentronic/horn is supplied 5V via a CIM-integrated resistor of 560 Ohm. When the horn switch is closed, the lead is grounded and voltage sinks to 0 V. The 2 leads go via coil springs to CIM. CIM transmits the switch status on the bus.