I'm not sure all the extra wires are necessary or even desirable. Much of the
problem of amp light glowing is due to poor conductivity between laminations
in the fuse block or poor connections to the fuse that serves the amp light,
turn indicator, etc.

For what it's worth:
I had seen this "redundant" wire on another Amazon in the past and at that time thought, "well, ain't hurtin' nothin."
After buying a brand new fuse box, I found no change in my dull-glow-amp-lite.
Thought I'd add to the 40 year old wiring, couldn't hurt. The glow was not so much after adding the redundant wire.
No doubt all Amazons that haven't by now, should get a new or rebuilt fuse box, rebuilt distributor (vacuum module or not) and Carbs at the very least:o)
Shayne.