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, Cluster and Panel Illumination for schematic and connector information. Diagrams By Number

Normal Operation

When the parking lamps are on, the Body Control Module (BCM) provides voltage to the hardwired dimmable illumination sources based on the Steering Column Control Module (SCCM) illumination messages that are sent over the network to the BCM.

- B1315:15 (Backlighting (Non Reflective Controls) Illumination Output: Circuit Short Battery or Open) - an on-demand DTC that sets when the BCM detects a short to voltage from the backlighting output circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- BCM

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

- Place the headlamp switch in the OFF position.
- Observe the parking lights.
- Are the parking lights illuminated?

Yes
REFER to Exterior Lighting Testing and Inspection to diagnose the exterior lamps always on.

No
GO to C2.

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

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

Yes
REPAIR circuit VLN04 (VT/GY) for a short to voltage. TEST the system for normal operation.

No
GO to C3.

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C3 CHECK FOR CORRECT BCM OPERATION

- Ignition OFF.
- Disconnect all the BCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM 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 BCM. 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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