Unknown cable/wire

[RJRavalli@xxxx]

I recently discovered an unconnected wire/cable that runs along
the floorboard of my 81 D and goes up into the consol along the
right-hand side of the driver's seat. It looks a little like a tv cable 
except the prong is thicker and longer. Can someone tell me what 
this is for?

(Also, underneath the dash I have a frayed wire that comes out of
the "white box" to the left of the steering wheel. What is this and
should I be overly concerned about it?) 

Thank you for any help and Merry Christmas, :)

Richard