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Home >> Mercury >> 1993 >> Villager LS >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panels - Analog >> System Tests >> Pinpoint Test A: Brake Warning Lamp System

Pinpoint Test A: Brake Warning Lamp System

NOTE: Go to TROUBLE SHOOTING  before starting pinpoint test. Identify system where problem is located. Find symptom in trouble shooting and go to specific pinpoint test step as directed by trouble shooting procedure.

  1. Check 10A Meter Fuse

    Check the 10A METER fuse located in the interior fuse panel. Is the fuse OK? If yes, see STEP 4. If no, go to next step.

  2. Check System (10A Meter Fuse)

    Turn key OFF. Replace the 10A METER fuse. Turn key ON. Inspect the fuse. Does the fuse fail again? If yes, go to next step. If no, see  4 .

  3. Check For Short Ground

    Turn key OFF. Remove the 10A METER fuse. Remove the instrument cluster. Disconnect all the instrument cluster connectors. Measure the resistance of the (Gray/Blue) wire between the right terminal of the 10A METER fuse and ground. See WIRING DIAGRAMS  . Is the resistance greater than 10,000 ohms? If yes, replace the 10A meter fuse and go to next step. If no, service the (Gray/Blue) wire between the interior fuse panel and the instrument cluster. See WIRING DIAGRAMS  .

  4. Check Power Supply To Instrument Cluster

    Turn key OFF. Remove the instrument cluster. Disconnect the black 12-pin analog instrument cluster connector or the 20-pin electronic instrument cluster connector. Turn key ON. Measure the voltage on Terminal No. 2I (Gray/Blue) of the black 12-pin analog instrument cluster connector or Terminal No. 1T (Gray/Blue) of the 20-pin electronic instrument cluster connector. See WIRING DIAGRAMS  . 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. See WIRING DIAGRAMS  .

  5. Check Brake Warning Lamp Bulb

    Turn key OFF. Remove the instrument cluster. Remove the brake warning lamp bulb on the instrument cluster. Measure the resistance between the terminals of the brake warning lamp bulb. Is the resistance approximately 15 ohms? If yes, go to next step. If no, replace the brake warning lamp bulb.

  6. Check Brake Warning Lamp Circuit (Analog Instrument Cluster)

    Key OFF. Remove the instrument cluster. Disconnect all of the instrument cluster connectors. Connect a test lamp between Terminal No. 2I (Gray/Blue) on the black 12-pin instrument cluster connector and Terminal No. 3G (Yellow/Purple) on the white 12-pin instrument cluster connector. See WIRING DIAGRAMS  . Key ON. Does the test lamp illuminate? If yes, go to next step. If no, replace the instrument cluster printed circuit board.

  7. Check Wire Between Instrument Cluster & Bulb Check Relay For Short

    Turn key OFF. Remove the instrument cluster. Disconnect the white 12-pin analog instrument cluster connector or the 20-pin electronic instrument cluster connector. Disconnect the low brake fluid level indicator switch connector located under the brake fluid reservoir. Remove the bulb check relay from the left hand engine compartment relay block. Disconnect the top black diode strip at the diode junction box located behind the instrument cluster. Measure the resistance of the (Yellow/Purple) wire between Terminal No. 3G of the white 12-pin analog instrument cluster connector or Terminal No. 1L of the 20-pin electronic instrument cluster connector and ground. See WIRING DIAGRAMS  . Is the resistance greater than 10,000 ohms? If yes, go to next step. If no, service the (Yellow/Purple) wire. See WIRING DIAGRAMS  .

  8. Check Wire Between Instrument Cluster & Bulb Check Relay For Open

    Key OFF. Remove the instrument cluster. Disconnect the white 12-pin analog instrument cluster connector or the 20-pin electronic instrument cluster connector. Remove the bulb check relay. Measure the resistance of the (Yellow/Purple) wire between the bulb check relay connector and Terminal No. 3G of the white 12-pin analog instrument cluster connector or Terminal No. 1L of the 20-pin electronic instrument cluster connector. See WIRING DIAGRAMS  . Is the resistance less than 5 ohms? If yes, go to next step. If no, service the (Yellow/Purple) wire. See WIRING DIAGRAMS  .

  9. Check RLY Coil Fuse

    Check the 10A RLY COIL fuse located in the interior fuse panel. Is the fuse OK? If yes, go to step  12 . If no, go to next step.

  10. Check System (10A RLY Coil Fuse)

    Turn key OFF. Replace the 10A RLY COIL fuse. Turn key ON. Inspect the fuse. Does the fuse fail again? If yes, go to next step. If no, go to step  12 .

  11. Check For Short Between Interior Fuse Panel & Bulb Check Relay

    Turn key OFF. Remove the 10A RLY COIL fuse. Remove the bulb check relay. Measure the resistance of the (Blue) wire between the right terminal of the 10A RLY COIL fuse and ground. Is the resistance less than 5 ohms? If yes, service the (Blue) wire between the interior fuse panel and the bulb check relay. If no, go to next step.

  12. Check Power Supply To Bulb Check Relay

    Turn key OFF. Remove the bulb check relay. Measure the voltage on the (Blue) wire at the bulb check relay connector. Is the voltage greater than 10 volts? If yes, go to next step. If no, service the (Blue) wire between the interior fuse panel and the bulb check relay. See WIRING DIAGRAMS  .

  13. Check Wire Between Bulb Check Relay & Diode Junction Box

    Turn key OFF. Remove the instrument cluster. Remove the bulb check relay. Disconnect the top black diode strip at the diode junction box located behind the instrument cluster. Measure the resistance of the (Blue/Yellow) wire between the bulb check relay connector and Terminal No. 6 of the diode junction box connector. Is the resistance less than 5 ohms? If yes, go to next step. If no, service the (Blue/Yellow) wire. See WIRING DIAGRAMS  .

  14. Bulb Check Relay Ground. Key OFF

    Remove the bulb check relay. Measure the resistance of the (Black) wire between the bulb check relay connector and ground. Is the resistance less than 5 ohms? If yes, go to next step. If no, service the (Black) wire. See WIRING DIAGRAMS  .

  15. Bulb Check Relay. Key OFF

    Remove the bulb check relay. Apply 12 volts to the (Blue) wire terminal at the bulb check relay. Measure the resistance between the (Yellow/Purple) wire terminal and the (Black) wire terminal on the bulb check relay at the following conditions. Are the resistances OK? If yes, go to next step. If no, replace the bulb check relay. See BULB CHECK RELAY RESISTANCE  . See WIRING DIAGRAMS  .
    BULB CHECK RELAY RESISTANCE

    Blue/Yellow Terminal Resistance
    Ground Less Than 5 Ohms
    Open Greater Than 10,000 Ohms

  16. Check Low Brake Fluid Level Indicator Switch

    Key OFF. Disconnect the low brake fluid level indicator switch connector located under the brake fluid reservoir. Gently remove the screen inside the brake fluid reservoir. Depress the brake fluid level float with a clean screwdriver. Measure the resistance between the terminals of the low brake fluid level indicator switch. Is the resistance less than 5 ohms with the brake fluid level float depressed, and greater than 10,000 ohms with brake fluid level float released? If yes, go to next step. If no, replace the low brake fluid level indicator switch.

  17. Check Wire Between Instrument Cluster & Low Brake Fluid Level Indicator Switch

    . Key OFF. Remove the instrument cluster. Disconnect the white 12-pin analog instrument cluster connector or the 20-pin electronic instrument cluster connector. Disconnect the low brake fluid level indicator switch connector. Measure the resistance of the (Yellow/Purple) wire between Terminal No. 3G of the white 12-pin analog instrument cluster connector or Terminal No. 1L of the 20-pin electronic instrument cluster connector and the low brake fluid level indicator switch connector. Is the resistance less than 5 ohms? If yes, go to next step. If no, service the (Yellow/Purple) wire. See WIRING DIAGRAMS  .

  18. Check Low Brake Fluid Level Indicator Switch Ground. Key OFF

    Disconnect the low brake fluid level indicator switch connector. Measure the resistance of the (Black) wire between the low brake fluid level indicator switch connector and ground. Is the resistance less than 5 ohms? If yes, go to next step. If no, service the (Black) wire. See WIRING DIAGRAMS  .

  19. Check Parking Brake Switch. Key OFF

    Disconnect the parking brake switch connector located on the parking brake pedal. Set the parking brake. Measure the resistance between the terminal on the parking brake switch and ground. Is the resistance less than 5 ohms with the parking brake set, and greater than 10,000 ohms with parking brake released? If yes, go to next step. If no, replace the parking brake switch.

  20. Check Wire Between instrument Cluster & Diode Junction Box. Turn key OFF

    Remove the instrument cluster. Disconnect the white 12-pin analog instrument cluster connector or the 20-pin electronic instrument cluster. Disconnect the top black diode strip at the diode junction box located behind the instrument cluster. Measure the resistance of the (Yellow/Purple) wire between Terminal No. 3G of the white 12-pin analog instrument cluster connector or Terminal No. 1L of the 20-pin electronic instrument cluster connector and Terminal No. 10 of the diode junction box connector. Is the resistance less than 5 ohms? If yes, go to next step. If no, service the (Yellow/Purple) wire. See WIRING DIAGRAMS  .

  21. Check Wire Between Diode Junction Box & Parking Brake Switch

    Turn key OFF. Remove the instrument cluster. Disconnect the top black diode strip at the diode junction box. Disconnect the parking brake switch connector. Measure the resistance of the (Green/Black) wire between Terminal No. 9 of the diode junction box connector and the parking brake switch connector. Is the resistance less than 5 ohms? If yes, replace the top black diode strip on the diode junction box. If no, service the (Green/Black) wire. See WIRING DIAGRAMS  .
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