Fuel Gauge: Sonata

Disconnect fuel sending unit harness connector. Connect a rheostat between ground and fuel sending unit harness connector Purple wire. Turn ignition on. Slowly change rheostat settings from 7 ohms to 95 ohms. Gauge should move slowly from FULL to EMPTY. If operation is not as specified, leave fuel sending unit unplugged and repeat test at Purple wire at instrument cluster. See WIRING DIAGRAMS . If gauge operation is as specified, repair faulty circuit between gauge and sending unit. If operation is not as specified, check for battery voltage and ground at fuel gauge. Inspect instrument cluster printed circuit and replace if necessary. If no problem was found, replace fuel gauge.