Horn switch (41)
Horn switch (41)
Used to control the horn. CIM sends the switch status on the bus.
Single pin switch integrated in the driver's airbag. The switch is connected to the Sentronic circuit on automatic cars.
The steering wheel buttons are resistive multiplexed (5V) and divided into 2 circuits; switches for Sentronic, horn and SET in one circuit and other buttons in the second. The 2 circuits have a common ground from the CIM. Each circuit has an extra resistor for diagnosing an open circuit. The lead for the Sentronic/horn/SET is fed with 5V via a 560 Ω resistor integrated in the CIM. When the horn switch closes, the lead is grounded and the voltage drops to 0V. All the leads go via a coil spring to the CIM. The CIM sends the status of the horn and the other buttons on the bus.
