Pinpoint Test A: No Power in All Ignition Switch Positions

Steering Column Switches

Pinpoint Test A: No Power in All Ignition Switch Positions

Refer to Wiring Diagram Set 13 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Power Distribution/SJB for schematic and connector information. Diagrams By Number

Normal Operation

The ignition switch receives fused battery voltage from Smart Junction Box (SJB) fuse 27 (20A) through circuit SBP27 (BU/RD). The ignition switch then sends voltage to various systems depending on ignition switch position. The ignition switch has 4 possible positions:

- OFF - No power on any circuits
- ACC - Power on circuit CDC33 (VT/GN)
- RUN - Power on circuit CDC34 (WH/OG)
- START - Power on circuit CDC35 (BU/WH)

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Ignition switch
- SJB


PINPOINT TEST A: NO POWER IN ALL IGNITION SWITCH POSITIONS

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

NOTE: Verify that battery voltage is 10 volts or greater.

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A1 CHECK AT THE IGNITION SWITCH FOR VOLTAGE

- Ignition OFF.
- Disconnect: Ignition Switch C250.
- Measure the voltage between ignition switch C250-4, circuit SBP27 (BU/RD), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
INSTALL a new ignition switch. REFER to Ignition Switch Ignition Switch. TEST the system for normal operation.

No
VERIFY SJB fuse 27 (20A) is OK. If OK, GO to A2. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation. Diagrams By Number

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A2 CHECK THE IGNITION SWITCH INPUT CIRCUIT FOR AN OPEN

- Ignition OFF.
- 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.




- Is the resistance less than 5 ohms?

Yes
GO to A3.

No
REPAIR circuit SBP27 (BU/RD). TEST the system for normal operation.

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A3 CHECK FOR CORRECT SJB OPERATION

- Disconnect: All SJB connectors.
- Check the SJB connectors for:

- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: All SJB connectors and make sure the connectors seat correctly.
- 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 Service and Repair. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

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