I recently purchased a 2012 mustang gt premium. I have noticed during idle when the electric cooling fan turns on my rpms drop slightly and my lights also dim slightly then returns to normal a split second after. It does with even with the a/c off. Does anybody elses 2011 or 2012 gt do this or does my car have some sort of issue. I actually called the dealership and spoke to the service manager and he said he has heard of this and it is a normal aspect of the car. Any info would be greatly appreciated.