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Test C: Incorrect Fuel Gauge Indication

NOTE: Fuel gauge indication will require at least 10 minutes to updated if fuel tank has less than 2.5 gallons in it.
  1. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Turn ignition switch to RUN position. Using NGS tester, select instrument cluster active command FUELLEVEL. Trigger, monitor and scroll FUELLEVEL at 0%, 50% and 100%. Fuel gauge should indicate empty at 0%, half at 50% and full at 100%. If fuel gauge responds as specified, go to next step. If fuel gauge does not respond as specified, replace instrument cluster.
  2. Turn ignition switch to OFF position. Disconnect fuel pump assembly harness connector C420. Using Instrument Gauge System Tester (014-R1063), connect one lead to Yellow/White wire terminal and the second lead to Black/Orange wire terminal at fuel pump assembly harness connector C420. Set gauge tester to 160 ohms. Turn gauge tester on. Turn ignition switch to RUN position, wait one second. Turn ignition switch to OFF position. Set gauge tester to 15 ohms. Turn ignition switch to RUN position, wait one minute. Fuel gauge should read empty or below. Turn ignition switch to OFF position. Set gauge tester to 160 ohms. Turn ignition switch to RUN position, wait one minute. Fuel gauge should read full or above. Turn ignition switch to OFF position. If fuel gauge operated as specified, go to next step. If fuel gauge did not operate as specified, go to step  5 .
  3. Visually inspect fuel tank for damage or deformation. If no damage exists, go to next step. If damage exists, replace fuel tank.
  4. Inspect fuel pump assembly for damaged wiring or connectors, and float and float rod for damage or obstruction. If problem exists, repair as necessary. If problem does not exist, replace fuel level sender.
  5. Disconnect instrument cluster harness connector C251. Turn ignition switch to RUN position. Measure voltage at terminal No. 19 (Yellow/White wire) at instrument cluster harness connector C251. See Figure . If voltage does not exist, go to next step. If voltage exists, repair short to voltage in Yellow/White wire.
  6. Measure resistance in Yellow/White wire between fuel pump assembly harness connector C420 and terminal No. 19 at instrument cluster harness connector C251. Resistance should be 5 ohms or less. Measure resistance between ground and terminal No. 19 (Yellow/White wire) at instrument cluster harness connector C251. Resistance should be greater than 10 k/ohms. If both resistances reading are as specified, go to next step. If either resistance reading is not as specified, repair open and/or short to ground in Yellow/White wire.
  7. Measure resistance between ground and terminal No. 8 (Black/Orange wire) at fuel pump assembly harness connector C420. Measure resistance between ground and terminal No. 20 (Black/White wire) at instrument cluster harness connector C251. If both resistance reading are 5 ohms or less, replace instrument cluster. If either resistance reading is greater than 5 ohms, repair open in appropriate wire.
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