Update: One step forward, two steps back. After re-installing the dash with the new circuit board, the fuel gauge rose to 1/8th full, which should be about right. I got so excited I took a spin to the closest gas station (PEMEX) to fill her up (for the first time in years) in order to gloat on the success of another repair.
When I arrived at the station the gauge was reading 1/8 full as stated above. As the norm, when the tank filled and the pump shut off, a large squirt of gasoline shot out of the filler tube onto the ground. I had warned the attendant beforehand, so his shoes did not get wet. It took 53.68 liters (about 14 gallons).
Got back in the vehicle for the short drive home. Alas, now the fuel gauge needle is all the way to the left on empty! How did I make things worse?
On the drive back, I looked at the speedo for the first time this morning to find it's working, but has a bounce of about 5 MPH. Then as mentioned in previous posts, the odometer only reads 1/10ths of a mile and does not advance the corresponding miles digits. Of course, I already knew that was the case.
Well, the wire at the gas tank must have fallen off either inside or outside the tank. I'll look into that situation later when I'm in the mood.
Since the coolant temperature gauge only rises when the wire is grounded, I ordered a Standard Motor Products TS17 sensor which should arrive in a couple of weeks (Rock Auto specifies TS18 for vehicles with A/C--I wonder why?)
Update: The fuel gauge and temperature gauges are both working again as of 10/10/24.