Home refrigerator thermistor sensors control. Assuming that the 50k resistor is the NTC, if the 6k switch is closed the relay will go off but if the 50k resistor is varied down below the switching level like 40k the relay will go back to on state. So the 50k resistor variation was assumed to be the NTC resistance and it actually depend on the coldness of the fridge. The LED is the express cool indicator. The 3 resistors are the level selectors, once you close any level selector switch the LED will go off.
