Pinpoint Test A: All Dimmable Illumination Does Not Dim
Instrument Cluster and Panel Illumination
Pinpoint Test A: All Dimmable Illumination Does Not Dim
Normal Operation
When the parking lamps are on, the dimmable backlighting intensity can be changed by pressing the instrument panel dimmer switch to the first detent up or first detent down. The instrument panel dimmer switch is a momentary contact switch. When the instrument panel dimmer switch is placed in the first detent up or down, the corresponding input signal is routed back to the SCCM (Steering Column Control Module) to an internal ground indicating a request to turn the dimmable lighting up or down. The SCCM (Steering Column Control Module) retains the last brightness setting between uses.
Based on the input received from the instrument panel dimmer switch, the SCCM (Steering Column Control Module) sends a message to the Body Control Module (BCM) over the High Speed Controller Area Network (HS-CAN). The BCM (Body Control Module) sends a network message to the backlit modules indicating the backlighting intensity level and a voltage to the hardwired dimmable illumination sources.
When the instrument panel dimmer switch is pressed to the second detent, the dome lamp request input circuit is routed to ground in addition to the instrument panel dimmer switch input circuit. The SCCM (Steering Column Control Module) needs both an instrument panel dimmer switch up/down input circuit and the dome lamp request input circuit to turn the courtesy lamps on or off from the instrument panel dimmer switch.
If the SCCM (Steering Column Control Module) detects a concern with the instrument panel dimmer switch up/down input circuit or the dome lamp request input circuit, the backlighting defaults to full nighttime brightness.
- DTC B1124:09 (Lamp Fade Control: Component Failure)- a continuous and on-demand DTC that sets when the SCCM (Steering Column Control Module) detects a short to ground from the instrument panel dimmer switch up/down input or dome lamp request input circuits.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Instrument panel dimmer switch
- SCCM (Steering Column Control Module)
PINPOINT TEST A : ALL DIMMABLE ILLUMINATION DOES NOT DIM
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
A1 CHECK THE RECORDED RESULTS FROM THE SCCM (Steering Column Control Module) ON-DEMAND SELF-TEST
- Ignition OFF.
- Review the recorded results from the SCCM (Steering Column Control Module) on-demand self-test.
Is DTC B1124:09 present?
Yes
GO to A2.
No
GO to A4.
A2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH
- Disconnect: Instrument Panel Dimmer Switch C2298.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SCCM (Steering Column Control Module) Self-Test.
- Clear the DTCs and repeat the SCCM (Steering Column Control Module) self-test.
Is DTC B1124:09 still present?
Yes
GO to A3.
No
INSTALL a new instrument panel dimmer switch. REFER to Instrument Panel Dimmer Switch . TEST the system for normal operation.
A3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SCCM (Steering Column Control Module) C2414A.
- Measure the resistance between the instrument panel dimmer switch, harness side and ground as follows:
Connector-Pin Circuit C2298-2 VLN36 (GY/OG) C2298-3 CLN55 (YE/VT) C2298-7 CLN56 (BN/VT)
Are the resistances greater than 10,000 ohms?
Yes
GO to A9.
No
REPAIR the circuit in question for a short to ground. CLEAR the DTCs. REPEAT the self-test.
A4 CHECK THE INSTRUMENT PANEL DIMMER SWITCH
- Disconnect: Instrument Panel Dimmer Switch C2298.
- Carry out the instrument panel dimmer switch component test.
Is the instrument panel dimmer switch OK?
Yes
GO to A5.
No
INSTALL a new instrument panel dimmer switch. REFER to Instrument Panel Dimmer Switch . TEST the system for normal operation.
A5 CHECK THE INSTRUMENT PANEL DIMMER SWITCH UP AND DOWN INPUT CIRCUITS FOR VOLTAGE
- Ignition ON.
- Measure the voltage between the instrument panel dimmer switch C2298-7, circuit CLN56 (BN/VT), harness side and ground; and between the instrument panel dimmer switch C2298-3, circuit CLN55 (YE/VT), harness side and ground.
Are the voltages greater than 5 volts?
Yes
GO to A7.
No
GO to A6.
A6 CHECK THE INSTRUMENT PANEL DIMMER SWITCH UP AND DOWN INPUT CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: SCCM (Steering Column Control Module) C2414A.
- Measure the resistance between the instrument panel dimmer switch C2298-7, circuit CLN56 (BN/VT), harness side and the SCCM (Steering Column Control Module) C2414A-19, circuit CLN56 (BN/VT), harness side.
- Measure the resistance between the instrument panel dimmer switch C2298-3, circuit CLN55 (YE/VT), harness side and the SCCM (Steering Column Control Module) C2414A-6, circuit CLN55 (YE/VT), harness side.
Are the resistances less than 5 ohms?
Yes
GO to A9.
No
REPAIR the circuit in question for an open. TEST the system for normal operation.
A7 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT AND RETURN CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: SCCM (Steering Column Control Module) C2414A.
- Ignition ON.
- Measure the voltage between the instrument panel dimmer switch, harness side and ground as follows:
Connector-Pin Circuit C2298-2 VLN36 (GY/OG) C2298-3 CLN55 (YE/VT) C2298-4 RLN29 (WH/OG) C2298-7 CLN56 (BN/VT)
Is any voltage present?
Yes
REPAIR the circuit in question for a short to voltage. TEST the system for normal operation.
No
GO to A8.
A8 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the instrument panel dimmer switch C2298-4, circuit RLN29 (WH/OG), harness side and the SCCM (Steering Column Control Module) C2414A-26, circuit RLN29 (WH/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to A9.
No
REPAIR the circuit for an open. TEST the system for normal operation.
A9 CHECK FOR CORRECT SCCM (Steering Column Control Module) OPERATION
- Connect all disconnected connectors.
- Disconnect all the SCCM (Steering Column Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SCCM (Steering Column Control Module) 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 SCCM (Steering Column Control Module). 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.