Instrument Cluster Removal

There is a weld splice somewhere buried under tape. Follow the other wires from that inst' panel connector or follow the wires away from the ignition switch.
Actually there are 2 weld splices. The one with larger gauge black wires is the one after the amp gauge, feeding headlight switch, ignition switch, fuse box, etc...
The black wire you're looking for comes from the other weld splice with smaller or mixed large and small gauge black wires ( I can't see the diagram ).