OK, maybe everyone already knows this, but just in case it helps someone some day... At least for 1957, the cigar lighter has an integral circuit breaker. If your cigar lighter (aka power port for your GPS) doesn't work, feel in back. There is a tab that pops out when the breaker is tripped. Push it back in to reset.

Jim - Erie Colorado, 1957 Country Sedan

To late for me, last year I replaced mine because it had power on the rear stud but none on the center contact inside. After I installed the new one I looked at the old and bound the button, pressed it and click I had continuity front to rear again.

Never saw a breaker mentioned anyware before