I have a 2000 Bonneville and all the lights(dash, interior, headlights) pulse up and down when the outside lights(headlights and tail lights) are on. There are short periods of time when they dont pulse but most of the time if the headlights are on its doing it.
Thanks I will do that. Also i have the fuel gauge problem(dosnt read below half tank) that i have been reading up on in this forum and it sounds like my light problem has nothing to do with fuel gauge problem.
Now that mine is doing it more often I can watch the gauge drop down below 14 and back up to 14.2+ I had AutoZone check the alternator while it was on the car and they think ití* the voltage regulator in the alternator.