Model S 70D, VIN 109xxx with a production date of October 2015: auto dimming mirrors sometimes do not work. I would estimate about 20% of the time. Unfortunately, I usually don't notice this until after I've pulled out of the parking lot to go home at the end of the work day. This hasn't been a big problem since I don't often have someone with high beams behind me, but when it does happen and my auto dimming isn't working (both rear view and side mirrors) it is slightly less than ideal. Is there a safe, quick fix I can employ while I'm driving? If there was an on/off switch for the auto dimming feature I'd try that as it would resolve the issue in my previous cars, but I'm not aware of this, and a search on this forum tells me there is no on/off switch for the mirrors.