Pulsating lights

OK-go out were it is dark raise the hood and look at the alternator to see if you can see any sparking (inside the alternator) that keeps time with your flicker/pulse. You may see some sparking at the brushes(normal). Other wise it has to be some thing with the regulator or its wiring. PS if you see a lot of sparking in the alternator it usually means worn out brushes.