Just a heads up for those of us that have this feature. Noticed on the way to work this morning that the rear view mirror (with the auto-setting on) was really shaded dark. It was cloudy and rainy and I couldn't figure out why the mirror shading was activating. I could turn off the auto and it would go back to normal. Then I realized that my parking permit for work, hanging from the mirror, which is slightly smaller than the rear view mirror might be the cause. I turned the auto back on and removed the permit and the mirror went back to normal. The permit was obviously shading the sensor array and making the auto-shade kick in.