Hello, I have a peculiar problem with my SLK R171, driving with the roof up the LCD display constantly changes from dim to bright, (depending on the intensity of the outside light conditions - sunny/bright to overcast/dim etc), but the LCD never actually fails so I am guessing that there is an ambient light sensor located somewhere? which is playing up. The confusion starts when I have the roof down, stowed that is, because the LCD display becomes bright and stays bright irrespective of the ambient light conditions. So, is there a sensor? and is it inside somewhere? Thanks.