Circuit breaker for head lights
Where is it located in the 98 crown Vic
If I remember those correctly it is part of the headlight switch and they reset themselves after a few minutes. If the headlights keep going off and then comeback on after a few minutes check the actual amperage draw the headlight have first and if it is within specs then replace the switch. After that consider converting to LED bulbs, but get a good set.
This is with auto lamps.