Hey guys, I'm new to the site and have a 2009 trailblazer. My low beam headlights in auto mode are always on, with the car in gear, even when it the sensor on the dash is in broad daylight. So, I have just been switching the lights completely off in the daytime, but I want to know why the automatic mode isnt working. Maybe a bad sensor? Is there anyway to test if it is bad other than just covering it up?