Fuel Gauge Inaccurate (Single Tank Except 4.3L)

Disconnect instrument cluster connector. Connect fused jumper wire between instrument cluster connector terminal No. 22 (Pink wire) and battery voltage. See Figure . Install another fused jumper wire between instrument cluster connector terminal No. 31 (Black wire) and ground. Connect one Red lead of Instrument Panel Tester (J33431-B) to instrument cluster connector terminal No. 16 (Purple wire). Connect other Red lead to ground.
Set resistance dial to zero ohms. Fuel gauge should indicate "E" or less. Set resistance to 90 ohms. After a short period, gauge should indicate "F" or greater. If fuel gauge does not operate as specified, replace instrument cluster connector. If fuel gauge does operate as specified, go to next step.
Remove fused jumper wire between voltage and instrument cluster connector. Install a fused jumper wire between ground and instrument cluster connector. Reconnect instrument cluster connector. Disconnect fuel pump and sender (gasoline) or fuel gauge sender (diesel) connector. Connect one Red test lead to fuel gauge sender terminal "B" (Purple wire). Connect other Red test lead to ground. Set resistance dial to zero ohms, then to 90 ohms. If fuel gauge does not operate, locate and repair high resistance in Purple wire between instrument cluster connector and fuel gauge sender. If fuel gauge does operate, go to next step.
Reconnect tester between fuel gauge sender terminals "B" (Purple wire) and "A" (Black/White wire). Set resistance dial to zero ohms, then to 90 ohms. If fuel gauge operates, replace fuel pump and sender (gasoline) or fuel gauge sender (diesel). If fuel gauge does not operate, locate and repair high resistance in Black/White wire between fuel gauge sender and ground.