Member VetteVet is real good with the lingo of electrical stuff.
Maybe he will see this and chime in for the rescue
I will try to help.
Take pictures of what you do in step by step (For your own records)
It would help if you could post some here also.
So,
Step 1: You have try Test light method= No light up
Step 2: You have disconnected the Alt. = Still battery drain.
Next ( my suggestion)
Step 3:Try unplugging the external regulator
Step 4: Take the fuses out 1 by one and keep track of what you do.
There is a diagram of the wiring harness here on the forum.
If it will help I can post a Link.
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