My brake light on the dash has been coming on pretty consistently for the last month, every time I hit the brakes. I knew the pads needed to be replaced, but thought something else was wrong as well, because of the light. I replaced the front pads and rotors this weekend, and now the light hasn't come back on at all. I've never heard of any type of sensor that detects brake pad wear, so what's up with the light? My pads weren't worn all the way down, so I shouldn't have been pushing enough brake fluid down there to trigger the sensor for low fluid.