Firewall plugs, parts wanted

[Eric Walter <ewalter@domain.elided>]

When my wife got home last night, she said that her turn signals ('73
scout) had stopped working altogether(previously they would light but
not blink, so she would provide the blink manually by turning them on
and off).
I went out and noticed that one of the firewall plugs was loose (pass.
side lower), when I tried to seat it more firmly, the receiving plug
didn't seem attached to the firewall very well. I'm going to try and get
my wife (with smaller hands) to try and hold it from the inside while I
plug it in.
I also noticed that there are two large bullet type plugs in the center
of this firewall plug that don't go anywhere, both inside and outside of
the firewall plug they just end in about a 1/4" of bare strands. Are
these just unused or did someone cut out some wire? Is this even the
plug that the turnsignals use?  Where is the flasher anyway?
My wife also wants a seatbelt for the pass. side and we also need a rear
seat. Any help appreciated,
Eric