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Pinpoint Test A: The Shift Interlock System Does Not Release/Lock Correctly

  1. A1 CHECK THE POWER SUPPLY TO THE BRAKE SHIFT INTERLOCK ACTUATOR 
    NOTE: Test Step A1 diagnoses why the brake shift interlock system does not release correctly.
    • Key in OFF position.
    • Disconnect: Brake Shift Interlock Actuator.
    • Key in ON position.
    • Apply the brake pedal.
    • Measure the voltage between the brake shift interlock actuator pin 3 harness side and ground.
      Fig 1: Measuring Voltage Between Brake Shift Interlock Actuator Pin 3 Harness Side And Ground
      G03882959Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes  : INSTALL a new brake shift interlock actuator. REFER to BRAKE SHIFT INTERLOCK ACTUATOR . TEST the system for normal operation.
    • No  : REPAIR circuit. RECONNECT all components. TEST the system for normal operation. If the shift interlock system does not lock correctly, GO to A2  .
  2. A2 CHECK THE POWER SUPPLY TO THE BRAKE SHIFT INTERLOCK ACTUATOR 
    • Key in OFF position.
    • Disconnect: Brake Shift Interlock Actuator.
    • Key in ON position.
    • Measure the voltage between the brake shift interlock actuator pin 1 harness side and ground.
    • Fig 2: Measuring Voltage Between Brake Shift Interlock Actuator Pin 1 Harness Side And Ground
      G03882958Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes  : GO to A3  .
    • No  : REPAIR circuit. RECONNECT all components. TEST the system for normal operation.
  3. A3 CHECK CIRCUIT FOR AN OPEN 
    • Key in OFF position.
    • Measure the resistance between the brake shift interlock actuator pin 2 harness side and ground.
      Fig 3: Measuring Resistance Between Brake Shift Interlock Actuator Pin 2 Harness Side And Ground
      G03882960Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : INSTALL a new brake shift interlock actuator. REFER to BRAKE SHIFT INTERLOCK ACTUATOR . TEST the system for normal operation.
    • No  : REPAIR circuit. RECONNECT all components. TEST the system for normal operation.