Fuel Gauge

The magnetic fields of two coils, which are at right angles to each other, move the fuel gauge pointer. The two coils are connected to each other; the fuel level Pulse/width Modulated (PWM) circuit from the Powertrain Control Module (PCM) connects at a middle point. Battery voltage is applied to the end of the coil at the "E" end, and to ground at the other coil's "F" end.

The fuel level sender resistance is proportional to the fuel level. The voltage across the sender is the fuel level input signal applied to the PCM on CKT 30 and CKT 452. The PCM provides a PWM fuel level output signal on CKT 455 (PPL/WHT) to the instrument cluster fuel gauge.

When the tank is low, the fuel level sender resistance is low. A larger current passes through the "E" coil 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 gauge is not affected by changes in the vehicle's electrical system.