Gents. I have a weird problem that I've never encountered before. The entire left gauge cluster of the instrument cluster has gone dead except for the lights, and there is a 'humming' sound somewhat analagous to the buzzer that turns on when you put the key in the ignition, but at a much lower volume. When this problem started, the tach also went dead simultaneously. The humming sound completely turns off when you engage the left or right turn signal, but returns once the signal is canceled either manually or as a result of turning the steering wheel. Further more, there is a clicking sound that emanates from the instrument cluster, which sounds like a 'tick tock' of a clock, with the tick having a lower dynamic value (i.e. not as loud) than the tock. I checked the fuse box, all fuses are the correct amperage and are relatively new (less than a year old) and in the correct slots. I can engage the rheostat and it works, however it doesn't 'dim' the lights--at about the halfway point of the turn of the rheostat knob, the lights turn off. I mention this in case anyone thinks it might be the rheostat. Anyone have a clue as to what might be causing this issue? I'm betting this is a known problem that has a super easy solution

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The buzz / click is probably coming from the turn signal clicker that probably resides in the cluster.

Sounds like a ground lifted and is causing the problem.

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

Sounds like back feeding from cracked fuse, check (roll) all fuses

"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. " " Sounds like back feeding from cracked fuse, check (roll) all fuses " Guys, I don't think this is from a fuse in the fuse box. I checked all the fuses, rolled them to make sure there wasn't a hidden crack in the metal, and confirmed they are all good. "The buzz / click is probably coming from the turn signal clicker that probably resides in the cluster. Sounds like a ground lifted and is causing the problem. " Does that mean that the turn signal switch stalk is still good? Where would I check the ground, at the multi-pin plug, or where the stalk meets the steering wheel column? As an additional note, my odometer doesn't work. Could the 'tick tock' be the speedometer cable trying to turn the odometer gauge, but the gauge is not responding but clicking instead? Also, you know how the buzzer will go off when the door is open and the key is in the ignition? I did this test. With the car turned on, I opened the door. I heard two distinct buzzing/humming sounds: 1) the buzzer for the door being open with key in ignition and 2) the aforementioned humming sound.

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The bolbs fitted will do no harm to the holders .Reason they melt is that owners uprate the bulbs , then as they get hot, will damage the bulb holders.

Gents, update. After triple checking the fuse box, come to find out that the metal filament of the fuse was broken in the weirdest place--right on the cap. This led me to replace it, and lo-and-behold, the entire instrument cluster sprung back to life! I subsequently checked every fuse in the box and on my other benzes. I no longer trust the visual method of checking these fuses.

Furthermore, the tick tock that I heard? The 999.9 mile counter on the odometer gauge cluster is no longer functioning. Every one tenth of a mile, the odometer ticks and tocks. Weirdly enough though, the main odometer continues to count the correct mileage. I will have to pull out the cluster and either disable the 999.9 counter or try to repair it.

In the meanwhile, I get an annoying tick tock every tenth of a mile

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