Nice to hear everything ok again. The serviceman was partly correct. There is a light sensor on the back of autodimming mirror, only thing is that it's only for the mirror. The mirror compares the reading on the mirror surface to reading from the sensor on the backside. If the difference is big enough, the mirror dims. Of course the backside sensor also detects if it's dark or not. If not dark, there's no point in dimming the mirror :) Yeah, I did know that. But the serviceman apparently NOT! He said, "We have 4 sensors here so we have some to take a look at". =D Then I corrected them ;) Toyotas have had those sensors for years in many models so they are not new. Thought anyone at Toyota would have known this but I was wrong... But anyway, good ending!