Mine will sometimes dim when I have just exited off of a highway and have stopped at a stop light.. While I sit there the dash will do a quick little dim and then comes back up. It's almost like it was used to receiving "easy energy" from the higher rpm's on the highway and it now has to adjust for the lower rpm's that the car is running at sitting at the light. I just purchased the car and have been looking at the boards and noticed yesterday that I still have what appears to be the original battery(all white battery) in the car. It's a 2006 so I'm thinking that I may want to perform a pre-emptive swap out of the battery to help avoid issues down the road..