The car has nothing else electrical added. Only mods so far were suspension and wheels.
The car is kept in a heated garage but it does not matter if the temperature is above or below 0 the lights still dim when the bass hits. I have tried it with nothing else on except the radio and the headlamps while driving, and same results.
The Battery is only a year old and no other electrical stuff have been acting up. The car starts up first time and everything else works fine, heater, rear defroster, wipers, etc.
Just a thought but does it matter that I grounded the Amp directly to the battery negative terminal rather than a clean chassis screw/point?
Unfortunatley if this contiues I will have to remove the 12" sub and try a lesser system maybe with 2x 6" or 8" subs with a combined total of 200w RMS.
Any one else have the same symptoms?