Problem solved.
I had previously reseated the gauge needle when I replaced the background to the gauge cluster. I put it at the "L" while the factory had put the needle going all the way to the bottom. That little bit at the bottom made a huge difference.
I did use a second gauge cluster to verify the first, but I'll give you one guess who had reseated that needle as well.
Lucky I had a third one on hand that had not been corrupted. It read just below center of the gauge. Perfect
Yeah I feel a little foolish.
It was an old-timer at my local auto parts store that insisted that the engine was not overheating and that having two bad gauges was entirely possible. The other clue was that the gauge went to halfway when I unplugged it. I don't know if that is what is supposed to happen - but it got my mind to the answer.
Anyway. Thank you guys so much for your help! I sincerely appreciate all the brain power!