Pinpoint Test A: No Power In All Ignition Switch Positions
Steering Column Switches
Pinpoint Tests
Pinpoint Test A: No Power in All Ignition Switch Positions
Refer to Wiring Diagram Set 13, Power Distribution/SJB for schematic and connector information. Diagrams By Number
Normal Operation
The ignition switch receives fused battery voltage from Bussed Electrical Center (BEC) fuse 68 (20A) along circuit 1050 (LG/VT), this voltage is then sent to the Smart Junction Box (SJB) for various systems depending on the ignition switch position. The ignition switch has 4 possible positions:
- OFF, there is no voltage sent to the SJB, but voltage is sent to the instrument cluster for the key-in ignition system. Refer to Instrument Panel, Gauges and Warning Indicators to diagnose any key-in ignition concerns.
- ACC, the voltage is sent to the SJB along circuit 1002 (PK/BK).
- RUN, the voltage is sent to the SJB along circuit 1044 (WH/YE).
- START, the voltage is sent to the SJB along circuit 1522 (DG).
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Ignition switch
- BEC
- 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 multi-meter probes.
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A1 CHECK THE VOLTAGE AT THE IGNITION SWITCH
- Ignition OFF.
- Disconnect: Ignition Switch C250.
- Measure the voltage between ignition switch C250-4, circuit 1050 (LG/VT), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to A3.
No
VERIFY BEC fuse 68 (20A) is OK. If not OK, refer to the Wiring Diagrams to identify the possible causes of the circuit short. If OK, GO to A2.
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A2 CHECK CIRCUIT 1050 (LG/VT) FOR AN OPEN OR A SHORT TO GROUND
- Disconnect: BEC Fuse 68 (20A).
- Measure the resistance between:
- ignition switch C250-4, circuit 1050 (LG/VT), harness side and BEC fuse 68 (20A), circuit 1050 (LG/VT), output side.
- ignition switch C250-4, circuit 1050 (LG/VT), harness side and ground.
- Are the resistances less than 5 ohms between the ignition switch and the BEC, and greater than 10,000 ohms between the ignition switch and ground?
Yes
REPAIR or INSTALL a new BEC as necessary. TEST the system for normal operation.
No
REPAIR circuit 1050 (LG/VT). TEST the system for normal operation.
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A3 CHECK THE IGNITION SWITCH
- Carry out the Ignition Switch Component Test.
- Is the ignition switch OK?
Yes
GO to A4.
No
INSTALL a new ignition switch. REFER to Ignition Switch Ignition Switch. TEST the system for normal operation.
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A4 CHECK CIRCUIT 1002 (PK/BK) FOR AN OPEN
- Disconnect: SJB C2280a.
- Measure the resistance between ignition switch C250-6, circuit 1002 (PK/BK), harness side and SJB C2280a-11, circuit 1002 (PK/BK), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A5.
No
VERIFY SJB fuses 20 (10A) and 21 (10A) are OK. If OK, REPAIR circuit 1002 (PK/BK). If not OK, refer to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation.
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A5 CHECK CIRCUIT 1044 (WH/YE) FOR AN OPEN
- Measure the resistance between ignition switch C250-1, circuit 1044 (WH/YE), harness side and SJB C2280a-36, circuit 1044 (WH/YE), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A6.
No
VERIFY SJB fuses 20 (10A) and 21 (10A) are OK. If OK, REPAIR circuit 1002 (PK/BK). If not OK, refer to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation.
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A6 CHECK CIRCUIT 1522 (DG) FOR AN OPEN
- Measure the resistance between ignition switch C250-7, circuit 1522 (DG), harness side and SJB C2280a-12, circuit 1522 (DG), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A7.
No
VERIFY SJB fuses 20 (10A) and 21 (10A) are OK. If OK, REPAIR circuit 1002 (PK/BK). If not OK, refer to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation.
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A7 CHECK FOR CORRECT SJB OPERATION
- Check SJB C2280a for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: SJB C2280a.
- Make sure the connector seats correctly, then operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new SJB. 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.
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