help- blue field wire grounded?

You bet. Ignition switch connector is easy to access I would start there. If the headlights are nice and bright, that shows that the RED ammeter feed through the bulkhead is likely OK, and that the "welded splice" is also likely OK

Here's the "MAD" article. This thing gives a good overview, regardless of what Slant Six dan thinks, and the diagram is an "easy" way to see basic power distro:

Catalog

amp-ga18.jpg

With the headlights on, you can also wiggle the bulkhead connector and see if they dim/ blink. Also reach up and feel the ammeter terminals if you can get your hand in there. See if they are warm or loose