voltage when running is same at bat and alt output 14.7 at idle.
figuring this loss of 1+ volt to the blue side of regulator from ballast to regulator when you plug it in is a head scratcher.
i have a 1973 fsm but apparently bulkhead in my 76 isnt the same.
im assuming the heavy blue feed exits bulk head and goes to alt and ballast and the smaller gauge blue from regulator is spliced into it along the way ? i did a recent engine install must of done something to wiring some were.