Discovery II
NAVIGATION SYSTEM
DESCRIPTION AND OPERATION
87-9
A = Distance, miles (km); B = Start/Finish point
Reset
If the navigation system malfunctions, a system reset can be triggered by simultaneously pressing the TP button and
multifunction button 1 or 3. The navigation CD will need to be installed after the system reset.
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.
