When I turn on my headlights, the dash lights and exterior lights of the car dim considerably. When I just have the running lights on, it does not seem to have that problem in the dash or markers. As I rev the engine up, the lights in the dash and exterior get brighter. And then as I come to a stop and depress the brake pedal bringing the car back to idle, the lights dim again. Step on the gas, the lights brighten and the process repeats itself. I assume this is related to a ground issue, but I am not certain. Would appreciate any thoughts on what would cause this and how I might remedy this problem. Thanks.