Hello, gmwrench; I'm back...
I went to the car the next day; the gauge was down to cold, so I started the car.
It ran fine, so I headed for home- 50 km./ 30 mi. away. After 4 or 5 mi. (when it warmed up), the gauge trotted on up to HOT and she lost her get-up-and-go, as before(engine protection mode).
I pulled over, opened the hood and disconnected the wires from the Temp.
sending unit. I then tested the harness as per my Haynes shop manual– run a jumper from the green wire terminal in the plug to ground. Nothing. The dash gauge didn't
move. So then I thought: I'll just leave the plug off and drive 'er home like that.
Wrong. Now it wouldn't start at all. Finally, I put a jumper between the green wire and
the orange w/black wire in the plug. It seemed to work: I drove home, the car ran well,
the Rad. cooling fans operated; I drove some to-day, also. What does this mean?