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Home >> GMC >> 1996 >> C3500 HD 6.5 F, Standard >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panel - 6.5L Diesel >> Testing >> Fuel Gauge >> Fuel Gauge Inaccurate (Dual Tanks)

Fuel Gauge Inaccurate (Dual Tanks)

  1. Ensure fuel tank is full. Disconnect IPC connector. Install fused jumper wire between IPC terminal No. 31 (Black wire) and ground. Install fused jumper wire between IPC terminal No. 22 (Pink wire) and voltage. Connect one Red lead of Instrument Panel Tester (J 33431-B) to IPC terminal No. 16 (Purple wire). Connect remaining Red test lead to ground.
  2. Set resistance dial on tester to one ohm. Fuel gauge should indicate empty after a short time. Set resistance dial to 90 ohms. Fuel gauge should indicate full after a period of time. If gauge indicates correctly, go to next step. If gauge does not indicate correctly, replace IPC.
  3. Remove tester and jumper wires. Reconnect IPC connector. Turn ignition on. Disconnect balance fuel sender connector. Disconnect fuel gauge sender. Connect instrument panel tester between balance fuel sender connector terminal "D" (Light Blue wire) and ground. Adjust tester to 45 ohms. Also connect an instrument panel tester between fuel sender or fuel pump and sender connector terminal "B" (Dark Blue/White wire) and ground. Adjust tester to 45 ohms.
  4. If fuel gauge indicates about 1/2 full, go to next step. If fuel gauge indicates much more or much less than 1/2 full, replace fuel pump balance module.
  5. Ensure rear fuel tank is full. Connect ohmmeter between balance fuel sender terminals "A" (Black/White wire) and "D" (Light Blue wire). If 90 ohms or more are present, replace fuel gauge sender. If less than 90 ohms are present, replace balance fuel sender.
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