Bulkhead connector
Time to get a wiring diagram and do some power tracing.
Yep.
Two ways to go about the problem solving. \
1. List the items that don't work and see if they share a harness connector.
2. List the circuits that don't work and trace them back to what they have in common.
The stripped down power feed diagram in
this post is the start of how you would trace.
You can use the FSM diagrams to se if the items you list are on the same circuit(s) and maybe a disconnected feed or blown fuse.
Go to the connectors section to find where the body connector is and what is on it. For some years its behind the driverside kick panel.
The FSM may or may not also have some cable diagrams.
They will look like the one FrenchDemon posted here
1973 Duster Electrical Issue
Then look up the connector and see what is on it. it will be CI some number