No Parking Lights

Looking for suggestions on a "No Parking Lights" stumper for my son and I. It's 1972 Duster 340, AT.
A few days ago my son noticed he had no parking lights. He does have turn signals, hazard flashers, and Hi and Lo beam headlights. No side markers, tail or parking lights, instrument panel lights (back lighting). All gauges work, oil light, ammeter, fuel, water temp, E-brake light and low oil light. His key-in ign buzzer works if you press on one of the fuses, however...if you pull the switch to turn on the parking lights, the buzzer immediately stops. All the wires leading in and out of the fuse block appear to be ok. Also, the key-in ignition light works by timing out normally.

Am I correct in my thinking that the power comes through the bulkhead connector to the headlight switch, then to the fuses and then lights?

So, can anyone offer some helpful suggestions?

Thanks!