67 c10 instrument panel schematic and 'terminal next to battery'

[67alldiy]

I am trying to locate where the wire that runs from the instrument panel, labeled 'terminal next to battery' runs to.

I know it runs to the fuse box then out from there. I have tracked down a loose wire, in the engine compartment, that does show connective between the two which is located, literally next to the battery and black colored.

I think this should just be connected to the ground of the battery, or a ground, at least my gut tells me this however the original owner had an inline fuse hooked up from this wire to an aftermarket cd player and my friend pulled it before I had the chance to get my eyes on it.

My dash lights do go a little crazy and after replacing turn signal switch and few other things I would like to get this figured out to put it back to original.

This is obviously an instrument panel with gauges an no dummy lights.