I have more tales of high strangeness.
Went back to work after posting this thread. While the tractor could still run, I had to unload a car carrier piled full of pieces of big American chestnut limbs that broke off the 130 year old tree a couple of nights back and bombed the seventh green of our disc golf course, mashing the basket pretty much flat. This was today's project and it was after the first trailer load that I took off for lunch, knowing I would have to refuel before returning to the task.
I refueled as planned and went back to the scene of the crime. I was hard at it when I looked to see how high the six gallons raised the gauge on the nine gallon tank. I noticed it was reading exactly what it was when I decided to fuel up. I did have the thought that the last fuel in the tank had gone too quickly. So, the gauge was probably already on the fritz. I was back here in the yard unloading when I switched off the key to see the symptoms I posted above. I immediately took the lower covers off and removed the ignition switch from the plastic cover. I moved wires at connections and popped the cover off the fuses and stared at them for a minute. I banged the ignition switch on something (caveman approach). Nothing changed or even flinched. I cussed my luck and came in and posted this thread.
At this point, all I wanted was to get the tractors back in their shed, take a shower, and go do 4th of July kinds of stuff. I put the LS in the shed first. But this time when I shut off the key, the fuel and temp gauges dropped all the way, but the hour meter went really nutz. Instead of simply remaining on as before, it first went blank, and then all 1s, then all 2s, then all 3s, so on up to all 0s, then blank again. It just kept repeating this pattern. I then started the engine again and it continued the repeated count, though the gauges did not register again either. I then raised the loader and lowered the brush guard so I could pull the ground off the battery.
Of course it all went off at that. I figured I would connect it back up just to see what would happen. What happened is everything is apparently back to normal. The gauges read correctly and the hours are about what they should be. I started and stopped the engine a couple times and no change. Everything working normally. I put the ignition switch back and the lower covers back and came in to report back to you all. I think I have seen LS's version of the Blue Screen of Death. I guess it just wanted a reboot. I would have bet it all on banging the ignition switch on the brake pedal arm, but then, I'm an old fart diesel submarine electronics tech. Put a computer chip in it and I am pretty much lost.