Help with no headlights. 1974 scamp. Blinkers come on instead...

If the switch doesn't send power out on the green wire, the circuit breaker inside the switch can be the fault. They typically cycle the lights on and off several times before failing completely. If there is a short somewhere, like at the bulkhead connection, that circuit breaker could turn the lights off faster than they could flash on.
I experienced circuit breaker failure before, headlights going off and back on at random, but don't recall it produced audible click. Its buried inside the switch so probably not.