Steering Wheel Switches (Navigation system)

Steering Wheel Switches

The steering wheel switches provide remote control operation for some of the navigation computer functions. The switches can be used to select between the radio/CD/navigation modes, to adjust the volume (in all modes) and to select search/preset up/down for radio and CD operation.

Remote Control Interface Unit

The remote control interface unit converts the analogue signals from the steering wheel switches into digital signals for use by the navigation computer. The remote control interface unit is installed in a bracket immediately below the navigation computer.

The radio remote switches form a resistance ladder between two wires with the resistance across wires dependent on which switch is pressed. The remote control interface unit monitors the two wires and converts their input into Instrument (I) bus protocol messages, which it outputs on a dedicated serial link to the navigation computer.