Pinpoint Test C: All Dimmable Switch Illumination Is Always On

Instrument Cluster and Panel Illumination

Pinpoint Tests

Pinpoint Test C: All Dimmable Switch Illumination Is Always On

Refer to Wiring Diagram Set 71 (Fusion/Milan/MKZ, Fusion Hybrid/Milan Hybrid), Cluster and Panel Illumination for schematic and connector information. 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.

- DTC B2A32 (LED Backlighting Output Circuit Open) - an on-demand DTC that sets when the SJB detects a short to voltage from the backlighting output circuit.
- DTC B29B7 (White Lighting Output Circuit Open) - an on-demand DTC that sets when the SJB detects a short to voltage from the white lighting (backlighting) output circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- SJB



PINPOINT TEST C: ALL DIMMABLE SWITCH ILLUMINATION IS ALWAYS ON

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

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C1 CHECK THE EXTERIOR LIGHTING


- Ignition ON.
- Observe the exterior lighting components.
- Are any exterior lighting components illuminated?

Yes
REFER to Lighting and Horns.

No
GO to C2.

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C2 CHECK THE SJB BACKLIGHTING OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Disconnect: SJB C2280b.
- Ignition ON.
- Do the dimmable backlighted components continue to illuminate?

Yes
REPAIR circuit VLN04 (VT/GY) (Fusion/Milan) or circuit VLN37 (BU/WH) (MKZ) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.

No
GO to C3.

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C3 CHECK FOR CORRECT SJB OPERATION


- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB 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. REFER to Body Control Systems. 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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