Lighting Of The Instrument Cluster
WARNING: This page is about a different car, the 2005 BMW 645Ci and 2004 BMW 645Ci. However, it is still accessible from the selected car via links, so may be relevant.
The instrument cluster has an integral power supply unit. The power supply is connected to terminal 30. The power supply provides the supply voltage for the instrument cluster.
This arrangement means that the lighting of the instrument cluster is independent of the onboard power supply. If the onboard power supply is disrupted (voltage dips), the brightness cannot fluctuate.
LEDs in BMW orange provide backlighting for the LCD display, the pointers of the analog instruments and the scale rings.
The pointers and the scale rings are illuminated when the lights are switched ON (= function display).
The display itself is not backlit unless it contains a reading.