More data on glowing ignition light

[jw@mail09.mitre.org (Joe Whalley)]

The light glows brightly when I turn the ignition on, then dims, but does not
go out when the engine starts. The voltage on the battery with engine off is
12.5, goes up to 13.6 at 3000 RPM. It seems the alternator is charging. Maybe
the indicating circuit is faulty? Where is the voltage regulator on a 72 Mk4?
Could it need a little adjustment to get the charging voltage up around 14?

Joe