Fuel Gauge

The magnetic fields of 2 coils move the pointer of the fuel gauge. The coils are at right angles to each other. Voltage applies to coil F from the IG fuse. The circuit divides at the opposite (ground) side of the coil. One path seeks a ground through coil E to G103. The other path seeks a ground through the variable resistor in the fuel level sender.

When the fuel level is low, the resistance in the fuel level sender is high. Current flows through coil F and coil E to ground at G103 because current always seeks the path of the least resistance. Because the length of the E coil winding is twice the length of the F coil winding, the magnetic field that the E coil generates is twice as strong as the magnetic field that the F coil generates. The magnetic field therefore pulls the pointer to the E position.

As the fuel level increases, the resistance in the fuel level sender decreases. Since current always seeks the path of the least resistance, more current begins to bypass the E coil and travel directly to ground through the fuel level sender. The coil F magnetic field then becomes stronger than the coil E magnetic field, causing the pointer to move toward the F position.