So you have some sort of Chrysler built vehicle with a grounded brush alternator. So we can guess its a pre-1970.
Is this correct? Yes this is correct. 1968 Barracuda 318 HEI.
See here for what is a grounded brush alternator: Identifying Chrysler Alternators (1960-1976)
I'm going to just assume nothing at the point, so my apologies for the questions.
When the engine is running what does needle on the gage labled 'alternator' do?
does it change between idle and say fast idle? There is just an ammeter gauge and it is just below center on the discharge side.
and if you know from using your multimeter:
What does the voltage across the battery read with the engine running? 11.5
What is the voltage at the alternator output terminal (the stud) ? Same
It should always be the same, key on, key off, engine running, engine not running. Both of those wires (battery positive and alternator output) are welded together under the dash.
Not sure what you are measuring here. volts to ground? Yes
If the ignition side of the regulator is not getting power with the key on (should show same voltage as battery) then there is a bad connection between the regulator ignition terminal and the key switch. This is assuming there is a good connection to the key switch from the battery and the alternator.
