I had a similar problem recently with my 201. The small fuse was blown, but one of the cluster lights was also out. Changed both cluster lights to LEDs because it is a known problem that the lights over time will start melting the plastic. I still have the slight humming noise though. Can't tell if it's like a vacuum noise or the noise from the speedometer because it seems to increase with RPM, but also some days it goes away.

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1990 190E 3.0L