Guys,
This ain't rocket science. The sender is not a thermocouple, a device that produces an emf when heated. It is a variable resistor with a negative heat coefficient, resistance goes down as heat goes up. There are other like the King-Seeley type but that's for another time. Buy yourself a variable resistor, like maybe 0-200 ohms, a couple of wire jumpers and hook the resistor up in place of the sender. Power up the gauge and vary the resistance. If everything is ok the needle will move from cold to hot. you can use an ohmmeter to measure the resistance from cold to hot. You then will know what the resistance range your sender needs to be. BTW, this test can also be used on the gas gauge. Good luck.
