Alternator gauge flutters

Sounds like it could be a flash/short of some kind.. does it do it with ALL lights off ? I had a light bulb rear running light element that did this in my ramcharger, it was shorting out some way or another.
I am sure you have tested the connections on your V.R and Alternator
What does it do when you start it up and turn the lights on and and keep it in park (not moving) ?