Broken field wire = not charging?

Well 13.5 is not "telling." Give it a "chance" so to speak. Run it a bit with lights, heater turned on. It should maintain 13.5 or so. If it drops down towards 12, then, not charging.

Clean up the voltage regulator mount, it MUST be grounded.
Will do. Weather sucks here right now, hopefully get her out tomorrow and see how she's doing.