Mercedes S Class W220 owners have many problems with this car instrument cluster. Problems include no lighting, partial lighting and / or flickering or intermittent lighting. Mainly to repair this dashboard you need replace defective lighting transformer to new one.
Also BUZ102S transistors can by defective - exchange it before transformer.
OE numbers were the item has/can been applied on:
The high voltage transformer have been successfully tested on the OE: 2205401411, 2205402811, 2205400911, 2205404611, 2205402011, 2205400211