Pinpoint Test B: All Dimmable Switch Illumination Is Inoperative

Instrument Cluster and Panel Illumination

Pinpoint Test B: All Dimmable Switch Illumination Is Inoperative

Refer to Wiring Diagram Set 71, Cluster and Panel Illumination for schematic and connector information. [1][2]Diagrams By Number

Normal Operation

When the parking lamps are on, the Smart Junction Box (SJB) sends a Pulse Width Modulated (PWM) voltage to the hardwired dimmable illumination sources based on the input received from the instrument panel dimmer switch.





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 SELF-TEST

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

Is DTC B2A33 or DTC B29B8 present?

Yes
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: [1][2]Diagrams By Number

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.

No
GO to B2.

B2 BYPASS THE SJB (Smart Junction Box)

NOTE: If the jumper wire fails, refer to the Wiring Diagrams to identify the possible causes of the circuit short. After the repair: [1][2]Diagrams By Number
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.

- Ignition OFF.

- Disconnect: SJB (Smart Junction Box) C2280B.

- For Fusion, connect a fused jumper wire between the SJB (Smart Junction Box) C2280B-39, circuit VLN04 (VT/GY), harness side and battery positive.





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





Do the backlighting components illuminate?

Yes
REMOVE the jumper wire. GO to B3.

No
REMOVE the jumper wire. REPAIR circuit VLN04 (VT/GY) (Fusion) or circuit VLN37 (BU/WH) (MKZ) for an open. CLEAR the DTCs. REPEAT the self-test.

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. CLEAR the DTCs. REPEAT the self-test.