headlights flashing

headlights flash after about 15 mins. I have replaced bulbs and put in new headlight switch in dash. no change.

Maybe the alternator belt is slipping? Or bad electric contact in alternator. Check voltage on battery, it should be steady.

Or the lamp harness is bad.

sounds like a possible bad ground. check the "free repair guides" thread for a link to the 97 FSM. trace the grounds and make sure they are snug and clean.

slos, when it starts to happen, hit an autozone and get a charging system test done. they can test the bat and alt while the car is running to see if the alt is failing under load.