Pinpoint Test A: No Power In All Ignition Switch Positions

WARNING: This page is about a different car, the 2013 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.

A1 CHECK THE VOLTAGE AT THE IGNITION SWITCH
- Ignition OFF.
- Disconnect: Ignition Switch C250.
- Measure the voltage between ignition switch C250-4, circuit SBP27 (BU/RD), harness side and ground.
  
  Fig 1: Measuring Voltage Between Ignition Switch C250-4, Circuit SBP27 (BU/RD) And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to A3.
- No : VERIFY Smart Junction Box (SJB) fuse 27 (20A) is OK. If not OK, REFER to the SYSTEM WIRING DIAGRAMS to identify the possible causes of the circuit short. If OK, GO to A2.
A2 CHECK THE IGNITION SWITCH INPUT CIRCUIT FOR AN OPEN
- Disconnect: SJB C2280A.
- Measure the resistance between ignition switch C250-4, circuit SBP27 (BU/RD), harness side and SJB C2280A-14, circuit SBP27 (BU/RD), harness side.
  
  Fig 2: Measuring Resistance Between Ignition Switch C250-4, Circuit SBP27 (BU/RD) And SJB C2280A-14
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to A3.
- No : REPAIR circuit SBP27 (BU/RD). TEST the system for normal operation.
A3 CHECK THE IGNITION SWITCH
- Carry out the IGNITION SWITCH . Refer to appropriate OEM WIRING COMPONENT TESTING for component testing .
- Is the ignition switch OK?
- Yes : GO to A4.
- No : INSTALL a new ignition switch. REFER to IGNITION SWITCH . TEST the system for normal operation.
A4 CHECK FOR CORRECT SJB OPERATION
- Check SJB C2280A for:
  - corrosion.
  - pushed-out pins.
  - spread terminals.
- Connect: Ignition Switch C250.
- Connect: SJB C2280A.
- Make sure the connectors seat correctly, then operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new SJB. REFER to MULTIFUNCTION ELECTRONIC MODULES . REPEAT the self-test.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST the system for normal operation.