The instrument cluster, along with the turn signal and wiper combination switch, can fail.Google+
Car Problem Reports
Mercedes-Benz 300SE Instrument Cluster, Turn Signal/Wiper Combination Switch May Fail
Mercedes-Benz 300SE Problem
Average Mileage: 163,000 mi (89,000 mi - 210,000 mi)
Visitor, 1990 Mercedes-Benz 300SE, 188,000 mi
first the wipers would not fully retract then the high beams went away now the wipers dont work either
Cluster rests itself randomly. Wipers may take up to 1 minute to start and signal lights may not work at all.