Removing connections from bulkhead!

Yes. There's a copy in the 67 Barracuda Service Manual Supplement. let me remember whether there's copy at Hamtramck Historical or mymopar.

I also have a schematic (stripped down version) of the main, ignition, and charge circuits posted a few places.
I'll post it here but the link will get you a bigger version,
Caivity N will match up and the other end is right at the switch.
I would check the wire to the ballast for a ground short. Clip a ohm meter probe on one end and the other probe to ground.
Understanding Charging Systems with Ammeter
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