Fuel Gauge

The magnetic fields of the 2 coils, the E coil and the F coil, move the pointer of the fuel gauge. The 2 coils are at right angles so that the magnetic fields interfere with each other. Battery voltage is available from the GAUGES fuse 4 through CKT 39 (PNK) to the instrument cluster when the ignition switch is in the RUN position or in the START position. The current flowing through the E coil places the pointer at E (empty) when little current flows through the F coil. When the current flow through the F coil is high, the pointer moves toward the F (full) indication.

The current that passes through the E coil has 2 paths to ground. Some of the current passes through the fixed resistance of the F coil and to ground G101 through CKT 451 (BLK/WHT). The rest of the current goes to ground through the variable resistance produced by the Vehicle Control Module (VCM) in gasoline vehicles or the fuel sender buffer module in diesel vehicles. The fuel pump and sender in gasoline vehicles or the fuel tank level sender in diesel vehicles produces a resistance of approximately 4 ohm when the fuel tank is empty. With this low resistance, most current passes through the fuel sender and not through the F coil. When the tank is full, the fuel sender's resistance is approximately 90 ohm. With this high resistance, more current flows through the F coil and the pointer moves to the F indication.

The fuel gauge's accuracy is adequate for normal operator usage. The fuel gauge provides a reasonable accurate indication of the level in the fuel tank. The fuel sender buffer module provides anti-sloshing in order to increase the fuel gauge performance. Changes in the battery voltage do not affect the gauge accuracy. However, non-linear construction in the fuel tank influences the accuracy of the gauge