Instrument and display lighting
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Instrument and display lighting
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In order to obtain good readability of the main instrument gauges, lamps and display in the dark as well as in daylight and to also obtain the best possible life expectancy of the light emitting diodes, the main instrument unit will control the illumination depending on the brightness in the cabin in combination with the rheostat position set by the driver.
The rheostat is connected to SID, in which the light sensor is also fitted.
SID sends continuous information on the following light values to the bus:
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Rheostat value, unit %.
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Rheostat Night Panel (this value is not used by the main instrument unit).
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Light intensity in the cabin, unit Lux.
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Display lighting, unit %.
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The main instrument unit uses the rheostat value to control the following instrument lighting:
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Coolant temperature gauge
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Selector lever indicator (automatic transmission)
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SID will send bus information Rheostat value 0% when the main headlights are off and fuse 15 for the daylight driving lights has been removed.
Diagnostics
The function has its own diagnostics in the sending system.
SID sends bus information Rheostat value 0% when the value of the light intensity in the cabin exceeds a certain level.
In order to increase the life expectancy of the light emitting diodes, the main instrument unit control module will turn off the following instrument illumination:
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Coolant temperature gauge
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For better visibility, the brightness of the indicator and warning lamps is set to two different levels. Low brightness at night and high brightness during the day.
SID sends bus information Cabin Light Intensity, unit Lux, and at a certain value, the main instrument unit control module will change the brightness of the LEDs listed below.
Common to these LEDs are that they are supplied with +15 from the main instrument unit and are grounded to the main instrument unit control module.
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Fuel reserve indicator lamp
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LH direction indicators
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RH direction indicators
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Diagnostics
The function has no diagnostics.
SID calculates a suitable value for the odometer display lighting using the rheostat value and the value for the light intensity in the cabin given by the light sensor.
When it is dark, the lighting is controlled by the rheostat value and when the light in the cabin increases it is controlled by the value of the light intensity in the cabin. This ensures that the odometer display will be easy to read in all lighting conditions.
SID sends the calculated value to the bus as Display Lighting Intensity, unit %.
The main instrument unit control module uses the value to control the odometer display lighting.
Diagnostics
The function has its own diagnostics in the sending system.
