71 dart instrument cluster

here's how the gages and sender work.
Thermal-Electric Gauges (Session 227) from the 1966 Master Technician's Service Conference

And there's the filmstrip that goes with that, along with a pdf version of the booklet at
Browse MTSC by Model Year – 1966 – MyMopar

For the sensor you can place it in boiling water and measure the resistance. Then check it at room temperature.

For testing the gages alone, you can apply a very low voltage, low power battery as a quick check, or supply power at 5 to 6 Volts, with a resistor in the return wire. Different resistors will mimic the sender in different conditions.
When working voltage limiter will pulse 0 to 8 volts when supplied power. It must have a return path for the current or the bimetal will not heatup and open.

for sensor i checked connection from the body of the sensor to battery - and it has connection. and then i checked ohms from sensor body to the 1 pin and it didint show anything. Does that mean sensor is bad?