i've noticed something similar, and though i haven't really spent the time to confirm, i'm pretty sure it's related to the light sensor, which also controls the auto lights as lenny noted (i turn mine off each time i get in the car). i've seen the dash lights change back and forth with it getting cloudy or stopping beneath an overpass in traffic then getting back to sunlight again (again, this is with the auto light feature turned off). hope that's all it is!