Pinpoint Test B: All Dimmable Switch Illumination Is Inoperative

Instrument Cluster and Panel Illumination

Pinpoint Test B: All Dimmable Switch Illumination Is Inoperative

Normal Operation

Based on input received from the instrument panel dimmer switch, the Smart Junction Box (SJB) sends a Pulse Width Modulated (PWM) voltage to the dimmable illumination switches.

- DTC B29B7 (White Lighting Output Circuit Open)- an on-demand DTC that sets when the SJB (Smart Junction Box) detects an open from the backlighting output circuit.

- DTC B29B8 (White Lighting Output Circuit Short to Ground)- a continuous and on-demand DTC that sets when the SJB (Smart Junction Box) detects a short to ground from the output circuit. This DTC also sets when fuse 10 (15A) has failed or is removed.

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- SJB (Smart Junction Box)

PINPOINT TEST B : ALL DIMMABLE SWITCH ILLUMINATION IS INOPERATIVE

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

B1 CHECK FOR RECORDED SJB (Smart Junction Box) DTCs FROM THE ON-DEMAND SELF-TEST

- Use the recorded results from the SJB (Smart Junction Box) self-test.

Is DTC B29B7 present?

Yes
GO to B2.

No
VERIFY the SJB (Smart Junction Box) fuse 10 (15A) is OK. If OK, GO to B2.

If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. After the repair: Electrical Diagrams

If no DTCs are present, TEST the system for normal operation.

If DTC B106E is present, CLEAR the DTCs and REPEAT the self-test (required to enable the backlighting output driver if DTC B106E is present). TEST the system for normal operation.

If DTC B106F is present, INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.

B2 BYPASS THE SJB (Smart Junction Box)

- Ignition OFF.

- Disconnect: SJB (Smart Junction Box) C2280B.

- NOTE: If the jumper wire fails, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. After the repair: Electrical Diagrams

If no DTCs are present, test the system for normal operation.

If DTC B106E is present, clear the DTCs and repeat the self-test (required to enable the courtesy lamp output driver if DTC B106E is present). Test the system for normal operation.

If DTC B106F is present, install a new SJB (Smart Junction Box). Test the system for normal operation.

Connect a fused jumper wire between the SJB (Smart Junction Box) C2280B-52, circuit VLN37 (BU/WH) and battery positive.





Do the backlighting components illuminate?

Yes
REMOVE the jumper wire. GO to B3.

No
REMOVE the jumper wire. VERIFY the SJB (Smart Junction Box) fuse 10 (15A) is OK. REPAIR circuit VLN37 (BU/WH) for an open. TEST the system for normal operation.

B3 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION

- Disconnect all the SJB (Smart Junction Box) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the SJB (Smart Junction Box) connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new SJB (Smart Junction Box). 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. RUN the on-demand self-test (required to clear certain DTCs). CORRECT any unresolved DTCs. CLEAR all DTCs. TEST the system for normal operation.