Pinpoint Test E: The Door Lock Control Switch Illumination Is Inoperative

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

E1 CHECK THE OPERATION OF THE DOOR LOCK SWITCH
- Operate the door locks from the suspect door lock switch.
- Do the door locks operate?
Result/Action to Take
- Yes: GO to E2 .
- No: REFER to door lock diagnosis in HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMS .
E2 CHECK CIRCUIT CBP41 (BU) OR CBB38 (GY/BU) FOR VOLTAGE
- Ignition OFF.
- Disconnect: Suspect Door Lock Switch.
- Ignition ON.
- Measure the voltage between the driver door lock control switch C541-3 circuit CBB38 (GY/BU), or the passenger door lock control switch C605-3 circuit CBP41 (BU), harness side and ground.
  
  Fig 1: Measuring Voltage Between Driver Door Lock Control Switch C541-3 Circuit CBB38 (GY/BU) And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes: INSTALL a new door lock control switch. REFER to HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMS . TEST the system for normal operation.
- No: REPAIR the circuit for an open.