I've got a MB 300SL -91.
I hear a buzzing noise from the passenger side of my dashboard (Electrical buzzing). It's buzzing while the engine is running and for about 3 sek after I've turned it off. Just when it stops a relay clicks.. It's not very loud but once you've heard it - you think of it all the time. Does anyone know anything about this??

I had a similar problem in my '97 E320 for almost a year. Turned out to be some A/C valves. As soon as I made an appointment to get it fixed (in warranty), it stopped and hasn't come back. Try listening in the engine compartment along the firewall, see if you can pin down the exact location. Ed