Instrument and display lighting: Notes

So that the main instrument unit gauges, lamps and displays will be easy to read in both daylight and at night, as well as to achieve optimum bulb life, the main instrument unit's control module regulates the lighting intensity of the display according to the brightness in the cabin and the rheostat setting selected by the driver.

The rheostat is connected to the SID where the light sensor is also fitted.

The SID unit continuously sends out information on the bus about the following light values: The SID unit continuously sends out information on the bus about the following light values:

Fig 1: Identifying Communication Diagram - Instrument And Display Lighting

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Identifying Communication Circuit Diagram - Instrument And Display Lighting

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Rheostat value, unit %.
Rheostat Night Panel (the value is not used by the main instrument unit).
Light intensity in the cabin, unit Lux.
Display lighting, unit %.