>Then it wouldn't be a single wire alternator, would it? Think about that
>for a moment. Alternators are, typically, 3 phase. That means 3 +ve
>power diodes, 3 -ve power diodes and 3 exciter diodes. If there is only
>one output wire, then all *rectification* and control has to be on-board.
When someone says "GM 1-wire alternator" they are talking about a series
of alternators introduced in 1970 or so, starting with the Delco 10SI and
including some more modern follow-ons. These alternators use internal
rectification and regulation (really just regulating pulses to the field
coil) and are very, very foolproof.
Because of this they are frequently retrofitted into older cars. I see
them on all sorts of older British cars as part of a conversion to a
modern 12V electrical system.
There isn't much to go wrong other than having the alternator go bad.
Mind you it is possible that the original poster's problem is that they
have a three-wire alernator or an alternator with external mechanical
voltage regulator and none of the other wiring is connected.
But if it is, breaking the connection between the alternator and the
battery and putting an ammeter in there should certainly show some
current. If not... maybe the alternator is not actually connected to
the battery but is going through an open shunt for the meter that isn't
working or something like that.
With cars that have been modified like this you don't get a proper wiring
diagram so you are going to need the continuity tester to see what is
going where. And yes checking the frame strap is always the first thing
to do (and make sure the frame strap isn't bolted to a solid block of bondo
"C'est un Nagra. C'est suisse, et tres, tres precis."