Those are related to it being dark out. If you are getting a voltage drop more than likely some big load is coming online like headlights.

Make sure the light sensor on the dash is clean. I'm not even sure where it is but I've covered it with my hand or iPhone and had my dashboard get dim on me. Do to have a level two scanner yet that you can actually monitor the light sensor?

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)