The car is equipped with numerous light sources for optimal lighting of interior instruments and controls.Some of these are lit with the ignition ON (INT), others with the side lights on, others are dimmable in accordance with a rheostat-controlled adjustment strategy managed by the Body Computer.The Body Computer manages the lighting - with the side lights on - of:- cigar lighter;- radio display (aftermarket version only) See E3510 RADIO - climate control system controls. See E6020 AIR CONDITIONING The Body Computer manages the dimmed instrument lighting with the display.If the side lights are deactivated, the display is 100% lit up and the brightness cannot be adjusted (dimmed). Adjustment is possible only with the exterior lights on. When the exterior lights are activated, the display brightness dims automatically to a preset value and the graphics and gauges light up. The driver can adjust the panel brightness and passenger compartment interior in general (to 8 levels) by pressing the + and - keys on the panel to the left side of the facia. The light intensity cannot be dimmed to zero.For more details See descriptions 5560 INSTRUMENTS All the other controls are lit up when the ignition is on (INT).