Bert,
I looked at Jolly's site but can't seem to find the right diagram.
I thought it was Jolly's,but Icannot find ti there either sorry for the misdirect
If you feel the wire is actually "IGN-unfused", that would indicate it is switched on and off with the key, but not supplied with protection. Was this obvious to you already...

Yes this was obvious- I am learning slowly ...:0
Does the fuse block on your '64 have notations next to the fuse holders. I have seen fuse blocks that had several terminals that were energized with the key and not fused. They accepted push on terminals and were intended for owner add on's I think.
These are the terminals in question,and the wire is attached with a push on terminal and terminates in a broken off wire at the other end.
I guess I would ask, what doesn't work with the red wire dangling?
The heater ...
I am sorry if that was not obvious from my earlier post. This is why I am stumped. In the diagrams that I have regarding the heater, it shows the wiring coming from the opposite end of the fuse. I thought that the power to these fused elements cameinto the fuse block from the power wire in the back of the block- but perhapsI am wrong and the power for this fuse comes from the broken red wire. My problem is that thisbroken red wire should not be hot if it is the power wire from the ignition swith,yet it sparks when it hits ground.... so?
it is late as usual and I am rambling - more details tomorrow or monday once my son is back home.