LEMON Manuals: Even more car manuals for everyone
Home >> Mercury >> 1993 >> Villager LS >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panels - Electronic >> System Tests >> Test C: Fuel Gauge & Low Fuel Warning Lamp Inoperative

Test C: Fuel Gauge & Low Fuel Warning Lamp Inoperative

NOTE: Do NOT start this test unless directed by a symptom diagnosis in FUEL GAUGE & LOW FUEL WARNING LAMP  under TROUBLE SHOOTING.
  1. Check the 10A Meter fuse located in the interior fuse panel. Is the fuse OK? If yes, go to step  4 . If no, go to next step.
  2. Turn key to OFF position. Replace the 10A Meter fuse. Turn key to ON position. Inspect the fuse. Does the fuse fail again? If yes, go to next step. If no, go to step  4 .
  3. Turn key to OFF position. Remove the instrument cluster. See ELECTRONIC INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Disconnect the 20-pin and the 12-pin instrument cluster connectors. Remove the 10A Meter fuse. Measure the resistance of the Gray/Blue wire between the right terminal of the 10A Meter fuse and ground. Is the resistance less than 5 ohms? If yes, service the Gray/Blue wire between the interior fuse panel and the instrument panel. If no, install the 10A Meter fuse and go to next step.
  4. Turn key to OFF position. Remove the instrument cluster. See ELECTRONIC INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Disconnect the 12-pin instrument cluster connector. Turn key to ON position. Measure the voltage between the Gray/Blue wire of the 12-pin instrument cluster connector and ground. See CONNECTOR IDENTIFICATION  . Is the voltage greater than 10 volts? If yes, go to next step. If no, service the Gray/Blue wire between the interior fuse panel and the instrument cluster.
  5. Disconnect the 12-pin instrument cluster connector. Measure the resistance of the Black wire between the 12-pin instrument cluster connector and ground. Is the resistance less than 5 ohms? If yes, go to step  8 . If no, go to next step.
  6. Turn key to OFF position. Disconnect the 12-pin instrument cluster connector. Disconnect the center Black diode strip from the diode junction box located behind the instrument cluster. Measure the resistance of the Black wire between the 12-pin instrument cluster connector and the pin 14 (Black wire) of the diode junction box. See Figure . Is the resistance less than 5 ohms? If yes, go to next step. If no, service Black wire.
  7. Turn key to OFF position. Disconnect the center Black diode strip of the diode junction box. Measure the resistance of the pin 15 (Black/Red wire) between the diode junction box and ground. Is the resistance less than 5 ohms? If yes, replace the center Black diode strip of the diode junction box. See DIODE STRIPS  under REMOVAL & INSTALLATION. If no, service Black/Red wire.
  8. Turn the key to the OFF position. Disconnect the fuel pump assembly connector. See Fig 1 . Connect Rotunda Instrument Gauge System Tester (021-00055) or equivalent between the Black/Red wire at the fuel pump assembly connector and ground. Turn key to ON position. Adjust the instrument gauge system tester to the resistances shown. See TESTING FUEL TANK SENDING UNIT  .
    TESTING FUEL TANK SENDING UNIT

    Fuel Gauge (Bar Transition) Approximate Resistance (Ohms)
    10-11 (Full Tank) 142
    9-10 110
    8-9 99
    7-8 88
    6-7 76
    5-6 (Half Tank) 64
    4-5 54
    3-4 47
    2-3 38
    1-2 (Empty Tank) 29
    0-1 20
    Low Fuel Warning Lamp On 32

    Do the fuel gauge and the low fuel warning lamp work properly? If yes, go to next step. If no, go to step  10 .

  9. Turn key to OFF position. Disconnect the fuel pump assembly connector. See Fig 1 . Measure the resistance of the Black wire between the fuel pump assembly connector and ground. Is the resistance less than 5 ohms? If yes, replace the fuel tank sending unit. See FUEL TANK SENDING UNIT  under REMOVAL & INSTALLATION. If no, service Black wire.
    Fig 1: Removing Fuel Pump Connector
    G00096552Courtesy of FORD MOTOR CO.
  10. Turn key to OFF position. Disconnect the 16-pin instrument cluster connector. See CONNECTOR IDENTIFICATION  . Disconnect the fuel pump assembly connector. Measure the resistance of the Blue/Red wire between the 16-pin instrument cluster connector and the fuel pump assembly connector. Measure the resistance of the Blue/Red wire between the 16-pin instrument cluster connector and ground. Is the resistance less than 5 ohms between the instrument cluster connector and the fuel pump assembly connector, and greater than 10,000 ohms between the instrument cluster connector and ground? If yes, replace the instrument cluster printed circuit board. See ELECTRONIC INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. If no, service Blue/Red wire.
  11. Turn key to OFF position. Remove the instrument cluster. See ELECTRONIC INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Disconnect the 12-pin instrument cluster connector. Turn key to ON position. Ground the Purple/White wire of the 12-pin instrument cluster connector. Does the low fuel warning lamp illuminate? If yes, replace the instrument cluster. If no, go to next step.
  12. Turn key to OFF position. Disconnect the 20-pin instrument cluster connector. Turn key to ON position. Measure the voltage of the Gray/Blue wire between the 20-pin instrument cluster connector and ground. Is the voltage greater than 10 volts? If yes, go to next step. If no, service the Gray/Blue wire between the interior fuse panel and the instrument cluster.
  13. Turn key to OFF position. Disconnect the 12-pin and 20-pin instrument cluster connectors. Measure the resistance of the Purple/White wire between Terminal "D" of the 12-pin instrument cluster connector and Terminal "J" of the 20-pin instrument cluster connector. Is the resistance less than 5 ohms? If yes, go to next step. If no, service Purple/White wire.
  14. Turn key to OFF position. Disconnect and remove the instrument cluster. Remove the low fuel warning lamp bulb. Measure the resistance between the terminals on the low fuel warning lamp bulb. Is the resistance approximately 16 ohms? If yes, replace instrument cluster. See ELECTRONIC INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. If no, replace the low fuel warning lamp bulb.
  15. Turn key to OFF position. Remove the instrument cluster. See ELECTRONIC INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Disconnect the 12-pin and 20-pin instrument cluster connectors. Measure the resistance of the Purple/White wire between terminal "D" of the 12-pin instrument cluster connector and ground. Is the resistance greater than 10,000 ohms? If yes, replace the instrument cluster. If no, service the Purple/White wire between terminal "D" of the 12-pin instrument cluster connector and terminal "J" of the 20-pin instrument cluster connector.
scientia non olet · About LEMON Manuals