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

A1 TEST THE BRAKE LIGHTS
- Apply brake pedal and view brake lights.
- Do brake lights illuminate?
- Yes : GO to A7.
- No : GO to A2.
A2 TEST FUSE 30 (15A)
- Key in OFF position.
- Check fuse: BJB Fuse 50 (15A).
- Is resistance of fuse 5 ohms or less?
- Yes : GO to A4.
- No : GO to A3.
A3 TEST THE CIRCUIT FOR A SHORT TO GROUND
- Key in OFF position.
- Disconnect: Brake Pedal Position (BPP) Switch.
- Measure the resistance pin 2 and ground.
  
  Fig 1: Measuring Resistance Pin 2 And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance 10 ohms or less?
- Yes : REPAIR circuit for short to ground. TEST the system for normal operation.
- No : GO to A4.
A4 TEST THE CIRCUIT FOR AN OPEN
- Measure the resistance between output side of fuse 50 (15A) and brake pedal position switch connector pin 2.
  
  Fig 2: Measuring Resistance Between Output Side Of Fuse 50 (15A) And Brake Pedal Position Switch Connector Pin 2
  Courtesy of FORD MOTOR CO.
- Is the resistance 5 ohms or less?
- Yes : GO to A5.
- No : REPAIR circuit for open. TEST the system for normal operation.
A5 TEST THE BRAKE PEDAL POSITION (BPP) SWITCH
- Measure the resistance of brake pedal position switch while open (OFF) and closed (ON).
  
  Fig 3: Measuring Resistance Of Brake Pedal Position Switch While Open (OFF) And Closed (ON)
  Courtesy of FORD MOTOR CO.
- Is resistance of switch greater than 10 ohms while OFF and 5 ohms or less while ON?
- Yes : GO to A6.
- No : INSTALL a new switch. TEST the system for normal operation.
A6 TEST THE CIRCUIT FOR A SHORT TO GROUND
- Disconnect: Shift Lock Actuator.
- Measure the resistance of pin 2 and ground.
  
  Fig 4: Measuring Resistance Of Pin 2 And Ground
  Courtesy of FORD MOTOR CO.
- Is resistance 10 ohms or less?
- Yes : REPAIR circuit for short to ground. TEST the system for normal operation.
- No : GO to A7.
A7 TEST THE CIRCUIT 810 FOR AN OPEN
- Measure the resistance between shift lock actuator pin 2 and brake pedal position switch connector pin 1.
  
  Fig 5: Measuring Resistance Between Shift Lock Actuator Pin 2 And Brake Pedal Position Switch Connector Pin 1
  Courtesy of FORD MOTOR CO.
- Is resistance 5 ohms or less?
- Yes : GO to A8.
- No : REPAIR circuit for open. TEST the system for normal operation.
A8 TEST FOR B+
- Key in ON position.
- Measure the voltage at shift lock actuator pin 3 and ground.
  
  Fig 6: Measuring Voltage At Shift Lock Actuator Pin 3 And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to A12.
- No : GO to A9.
A9 TEST FUSE 15 (7.5A)
- Key in OFF position.
- Check fuse: Fuse 15 (7.5A).
- Is resistance of fuse 5 ohms or less?
- Yes : GO to A11.
- No : GO to A10.
A10 TEST THE CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance at pin 3 and ground.
  
  Fig 7: Measuring Resistance At Pin 3 And Ground
  Courtesy of FORD MOTOR CO.
- Is resistance 10 ohms or less?
- Yes : REPAIR circuit for short to ground. TEST the system for normal operation.
- No : GO to A11.
A11 TEST THE CIRCUIT FOR AN OPEN
- Measure the resistance between output side of fuse 15 (7.5A) and the shift lock actuator pin 3.
  
  Fig 8: Measuring Resistance Between Output Side Of Fuse 15 (7.5A) And Shift Lock Actuator Pin 3
  Courtesy of FORD MOTOR CO.
- Is resistance 5 ohms or less?
- Yes : GO to A12.
- No : REPAIR circuit for open. TEST the system for normal operation.
A12 CHECK THE CIRCUIT FOR AN OPEN
- Measure the resistance of shift lock actuator pin 1 and ground.
  
  Fig 9: Measuring Resistance Of Shift Lock Actuator Pin 1 And Ground
  Courtesy of FORD MOTOR CO.
- Measure the resistance of shift lock actuator pin 6 and ground.
  
  Fig 10: Measuring Resistance Of Shift Lock Actuator Pin 6 And Ground
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : Shift lock actuator is not serviced. INSTALL a new steering column. REFER to STEERING SYSTEM-GENERAL INFORMATION . TEST the system for normal operation.
- No : REPAIR circuit for open. TEST the system for normal operation.