A vehicle rearview mirror system includes an electro-optic reflective element, an ambient light sensor that is operable to sense ambient light, a glare light sensor that is operable to sense glare light and a circuit that is responsive to the ambient glare light sensors which establishes a reflectance level of the reflective element. The circuit includes a sensor-responsive device and a controller. The sensor-responsive device produces an output that is a function of light sensed by glare and ambient light sensors. The controller connects one of the glare and ambient light sensors at a time with the sensor-responsive device to establish glare and ambient light levels and thereby the reflectance level of the reflective element. The mirror system may include a display operable to project light through the reflective element and may control the intensity of the display as a function of the glare light and ambient light.