I am thinking of moving the sensor in the rear view mirror to the top of the mirror. You can watch the line of light from the car behind you. The fin on the back of the car blocks the sensor all the time. The line of light always hits the top of the mirror. I wonder how hard it would be to drill a hole in the top and move the sensor.
i had similar problems in a 2001 subaru ll beaner wagon. the rear seat middle headrest put the photocell in shadow. i just removed the headrest and it was good to go 90% of the time. i'll be happier to manually switch it.
I read about flipping the mirror over a while ago. I was able to flip it over with out a problem. When it was flipped over I could not get it in a position to see out the back window. I tried every option. Since I posted this I have found that you can adjust the rear view mirror up and down. I have it pushed all the way up to the black clamp. This seems to help.
In another thread a poster suggested to artificially darken the photocell on the front of the mirror with some filtered plastic. The purpose was to raise the ratio of brightness to darkness so the mirror darkens at lower rear light levels than the default design. But yes, that spoiler is what's really the problem.
