The rain sensor in my recently acquired E70 does not work.

It does seem to calibrate correctly with an Autologic, (all three values at or very close to 1200.) It does not show any faults.

When I got the car, the plastic cover on one side of the mirror support was missing, so that's a clue that something could be amiss or was tampered with. Doesn't the sensor come with the windshield? Is it possible that the windshield was replaced with the wrong one? One thing I noticed, was that there only appears to be one "eye" in the round sensor window. Another similar X5 I looked at had a second "eye". Certainly my headlights turn on automatically as they should.

If the determination is that everything is correct, but my sensor is bad, can it be replaced? Or do I have to replace the windshield? Any ideas?

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2014 BMW 328i Xdrive
2011 BMW 335i M-Sport
2008 BMW X5 4.8i Sport
2000 BMW 528i 5sp