Should car still run on alternator with ground terminal off battery?

bobg450 said

OK, here's my 2C- Connect a voltmeter to your battery with the engine running. Should read about 14 VDC. If it's not and dropping, go to the field lead on the back of the alternator (small wire) and you should read something. If not, then the voltage regulator or it's wiring are not doing their job. If you do read something, you either have a bad alternator or bad ground somewhere. Mine was a bad voltage regulator. It was that simple, for me.

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Sorry but it's NOT (quite, always) that simple. It "can be" but maybe "isn't"

I tend to divide the charging system into "rough blocks"

"Not in order"

"The parts".......alternator, regulator, and sometimes, the battery

"The output" circuit, IE the path all the way from the alternator output stud to the battery. On unmodified cars, there is at least 5 or 6 major terminals in the path that can fail

"The field" wiring. This includes the path from the ignition switch, through the bulkhead to the voltage regulator, and onto the alternator field. On a 70 / later, this also must include the second blue field wire.