Unless both of us are somehow missing something here it is starting to look like the gauge has a problem. Are you for certain getting 12V into the input side of the regulator?
Ok, so measured and input side of regulator is showing 11v. Not 12v. Even plugged in the battery tender thinking i ran down the battery with all the testing.....re-measured, same outcome....and yet, the other studs (temp & alt) are getting 4.9v. I'm at a loss. This thing is on its own agenda.