Fuel Gage

The pointer of the Fuel Gage is moved by the magnetic fields of two coils. The coils are at right angles to each other. Battery voltage is applied to the EMPTY coil and the circuit divides at the opposite end of this coil. One path continues to ground through the FULL coil. Another goes to ground through the variable resistor of the Fuel Level Sender.

When the tank is low, the resistance of the Fuel Level Sender is low. A large flow of current passes through the EMPTY coil and the Fuel Level Sender Resistor. This pulls the pointer towards EMPTY on the scale. When the tank is full, the Fuel Level Sender Resistance is high. More current now flows through the FULL coil, moving the pointer to FULL on the scale. With two coils operating the pointer, the Fuel Gage is not affected by changes in the voltage of the system.