Fuel Gauge

The magnetic fields of two coils, which are at right angles to each other, move fuel gage pointer. Battery voltage is applied to the E coil, and the circuit divides at the coil's opposite end. One circuit goes to ground through the F coil. Another goes to ground through the variable fuel gage sender resistor.

When the tank is low, the sender resistance is low. A larger current passes through the E coil and the fuel gage sender resistor to move the pointer towards E on the scale. When the tank is full, the sender resistance is high. More current now flows through the F coil, which moves the pointer towards F on the scale.

With two coils operating the pointer, the gage is not affected by changes in the vehicle's electrical system.