The regulator is mounted on the back of the alternator. Output can be
measured on the post terminal that the red wire goes on, on the back of the
alternator.

My best guess leads to the battery being bad. A good test would be to jump
start the van, and measure the voltage across the battery terminals with the
engine running. You should see around 13 volts. Then turn off the engine,
and crank it with the voltmeter across the battery. The voltage should drop
to about 10 while cranking. If it suddenly drops to 6 or less (zero!), then
you have a bad battery or battery connection.

Good luck,
TomC

> It was 10 degrees here in Rochester this past Wednesday.  Went out to
> start the
> bus and no go.  Battery dead.  Jump-started, ran well.  Got to work, shut
> off,
> tried to restart, and nothing.
>
> Last night tried to do a little investigation in to why this might happen.
> Jump-started again & ran fine.  Looked into engine bay to confirm that the
> alternator was turning - yes.  Removed battery cable from positive battery
> terminal - engine still ran.  Shut off engine, reconnected cable, and
> tried to
> restart - dead.
>
> Battery was purchased new May 99.  Alternator is original.  Any ground
> points I
> could find were cleaned 11/26.
>
> My questions:  Where is alternator output voltage measured?  Where is the
> voltage regulator?  I always thought it was part of the alternator.  Does
> this
> sound like a bad battery cell, a bad voltage regulator, or time for an
> alternator replacement?
>