Has anybody noticed that at the left and right bottom corners of the screen, there is what looks like to be a climate control symbol (looks like an arch) it's red and blue, one says driver and the other is for passenger. It only shows up once in a while and I can't figure out what it's for..or why it comes on or goes off on it's own. How do you turn it on? What is this??? Any info much appreciated!! Thanks! 