Just looked at this on my 71 last week. Black wire on battery side of solenoid connects with bullet connector to this wire behind ampmeter. Make sure fueling at solenoid is still intact. This loops back to the alternator and feeds fuse box, ignition and I think headlights directly off the wire with a 4 way tap buried in harness. There should be another fuse link at alternator. Current flow from battery to load or alternator to battery deflects the ampmeter in dash.
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