I once had a strange battery drain also. I used the light trick (mentioned
in an earlier email) and pulled each wire off until I found it. Turns out it
was a bad mast jacket bearing. I think that's what it's called. It is the
bearing at the top of the steering column that has the brass ring slider for
the horn button in the steering wheel. I guess there was a small current
leakage through the side of the housing.
In any case, use a light and disconnect until you narrow it down.
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