1990 Cutlass lights flickering

Wife's car. I just noticed it as I was putting on new rear calipers, etc. The lights seem to pulsate about 2-4 times sec. Not all the way off, but bright, then brighter. I don't have an analog voltmeter, and my digital doesn't show pulsations, probably some kind of damping circuit. Anyway, before I start pulling fuses & such, has anyone run into this? The voltage at idle is 14.1, and with everything but the A/C (non functioning)on, it holds 13.6, with no drop after 10 minutes. She says she's never noticed it, and hasn't had any starting problems.