Pinpoint TEST I: THE SHIFT INTERLOCK SYSTEM DOES NOT RELEASE/LOCK CORRECTLY

WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.

Test Step

I1 CHECK THE POWER SUPPLY TO THE SHIFT LOCK ACTUATOR
NOTE: Test Step I1 diagnoses why the shift interlock system does not release correctly.
- Key in OFF position.
- Disconnect: Shift Lock Actuator.
- Key in ON position.
- Apply the brake pedal.
- Measure the voltage between the shift lock actuator pin 3 harness side and ground.
  
  Fig 1: Checking Power Supply To Shift Lock Actuator
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
  Yes
  
  INSTALL a new shift lock 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 I2.
I2 CHECK THE POWER SUPPLY TO THE SHIFT LOCK ACTUATOR
- Key in OFF position.
- Disconnect: Shift Lock Actuator.
- Key in ON position.
- Measure the voltage between the shift lock actuator pin 1 harness side and ground.
  
  Fig 2: Checking Power Supply To Shift Lock Actuator
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
  Yes
  
  GO to I3.
  
  No
  
  REPAIR circuit. RECONNECT all components. TEST the system for normal operation.
I3 CHECK CIRCUIT FOR AN OPEN
- Key in OFF position.
- Measure the resistance between the shift lock actuator pin 2 harness side and ground.
  
  Fig 3: Checking Circuit For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
  Yes
  
  INSTALL a new shift lock 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.