Fuel Gauge

NOTE: Before testing, ensure all fuses and grounds are good. Unless gauge is known to be defective, check sending unit and wiring circuit first.

To get to fuel tank sending unit connector, remove rear bumper. Using test light, backprobe Yellow/Red wire terminal of sending unit connector. Turn ignition on. Test light should light dimly and fuel gauge pointer should fluctuate toward full position within a few seconds.
If test light does not light, repair wiring circuit. See appropriate chassis wiring diagram in WIRING DIAGRAMS. After repair, use voltmeter to ensure 2-7 volts are supplied to Yellow/Red wire terminal at tank sending unit connector with ignition on.
If test light does light in step 1), but gauge does not fluctuate, remove instrument cluster. See INSTRUMENT CLUSTER . Attach ohmmeter leads across fuel gauge terminals on back of instrument cluster. See Fig 1 .

Fig 1: Testing Fuel Gauge Resistance (Metro - Tracker Similar)
Courtesy of GENERAL MOTORS CORP.
Resistance should be about 70 ohms. If resistance reading is not as specified, replace fuel gauge.