A vehicle rearview mirror system includes a rearview mirror assembly having an electro-optic reflective element, a housing for the reflective element and a control establishing a reflectance level of the reflective element. The control includes a circuit board having opposite sides and at least two photo-sensors on one of the sides. The system further includes at least one light conduiting element adapted to expose one of the at least two photo-sensors to a light environment that is different from the light environment to which the other of the at least two photo-sensors is exposed.