Fuel Gauge: Description and Operation

CIRCUIT OPERATION
A potentiometer is built into the fuel sender assembly. When the fuel tank is full, the resistance throughout the potentiometer is approximately 88 ohms, and at empty, the resistance is approximately 1.0 ohms. The fuel gauge applies voltage through CKT 30 to the potentiometer. As the resistance of the potentiometer decreases, the fuel gauge senses a smaller voltage drop across the potentiometer, indicating a lower fuel level. As the resistance of the potentiometer increases, the fuel gauge senses a larger voltage drop across the potentiometer, indicating a higher fuel level.