Dash Power Feed Confusion

Also we need to know WHAT IN THE HECK you are working on, year make and model. And whether it is factory stock wiring, been hacked up, or partially or fully rewired at some point "if you know."

THE PHOTO of the red wire suggests you MAY have what is known as "police fleet taxi" wiring which was optional and used with heavy duty 65A alternators. This took the big ammeter wires OUT OF the bulkhead connector and ran them through grommets in the firewall, although I don't remember there being multiple wires through one grommet as you are showing