Easy problem to solve. Use a variable resistor around 0-100 ohms. One lead to wire to gauge, other wire to ground. Key on. Vary resistor till you peg both ends of gauge. Read resistance of the resistor at both 0 and full scale and you have it. Problem is getting parts person to sell you the sensor when only knowing the resistance value.
You are correct. That would be the scientific way to do it! I was hoping someone just knew off the top of their head what they were. Like the common fuel gauges that most remember.
