I have a 1980 W126 280SE Euro model that had the pulley bolts on the harmonic balancer fail. When fixing this i found what appears to be a sensor that looks like it had been smashed, perhaps when the pulleys let go. Car seems to run fine but I am thinking this has been this way since before I bought it. This likely happened a while ago because there were no clean marks like it had just been damaged. I hangs next to the power steering pump. Any ideas? The only thing I can think of is that the Tach is not working. Not sure if it is related but was thinking it may be a crank sensor of some sort. Thanks for the help.

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Currently
1991 Mazda Miata 174000
1991 Subaru 189,000 Winter beater

got rid of:
1984 VW Vanagon 195,000
1976 350SE Euro 185,000 KM
1973 280SE 4.5 (boy do I regret that)
1980 280SE European W126 4 speed manual (miss it)
1989 BMW 735iL 119000 (good riddance)