Fuel Gauge Inaccurate, Erratic Or Always Indicates Empty
- Turn all accessories "OFF". Turn ignition switch to "RUN" and note number of bars brightly displayed on gauge. Turn ignition "OFF". Turn fan to "HIGH" and push cigarette lighter "IN". Turn ignition switch to "RUN". If fewer bars brightly displayed, service fuel gauge ground circuit A7 bus bar. If same number of bars are displayed, proceed to step 2).
- Check for loose, corroded or damaged connection at sender and sender ground (in trunk). Check resistance of circuit 57 (Black). If less than 1 ohm , proceed to step 3). If greater than 1 ohm, service wiring as necessary.
- Connect 72 ohm resistor to sender wiring connector. Turn ignition switch to "RUN". Fuel gauge should indicate 10-13 bargraph segments after prove out complete. If okay, proceed to step 4). If not okay, proceed to step 5).
- Turn ignition switch "OFF". Replace 72 ohm resistor with 10 ohm resistor and turn ignition switch "ON". Fuel gauge should indicate 0-1 bargraph segment along with flashing ISO symbol after prove out complete. If okay, perform fuel sender resistance tests. If not okay, proceed to step 5).
- Turn ignition switch "OFF" and remove resistor from fuel sender connector (leave disconnected). Remove White fuel wire from rear of fuel gauge and measure resistance to vehicle ground. If resistance is greater than 10,000 ohms, proceed to step 6). If less than 10,000 ohms, service wire as necessary.
- Short fuel sender connector with jumper wire. Measure resistance between fuel wire (White) and vehicle ground. If less than 3 ohms, proceed to step 7). If greater than 3 ohms, service wire.
- Turn ignition switch to "ON" and measure voltage between "IGN" and "GRD" terminals of fuel gauge. If 10 volts or greater, replace fuel gauge. If less than 10 volts, service power circuit as necessary.