Gocart879,
WOW..fire engine stuff, weird and pricey. Some unsolicited and unprofessional observations.
If you treat this as a alternator with external regulator, you will have to figure out how to put the alternator into full field charge manually to prove it works and put the blame on the regulator or maybe those 'strange two wires'.
The rectifier is external and probably isn't contributing to the no charge situation. The fact that is a very expensive 6 volt alternator doesn't mean it 'tests' any different than a 12 volt externally regulated unit.
A internally regulated alternator is put into full field charge by inserting a small pin/nail/paperclip into a hole in the case to tell the regulator to 'do its thing' with vigor.
I have NO clue how you full field charge test a setup like yours. Maybe you do know how, and have done it. Without being confused by all the extra 'fire engine stuff', the fact remains that it is either being told to charge, and can't..or it isn't being told to charge.
Have you thought about a auto electric shop for some help or guidance.
Stuart
