Pinpoint Test C: All Control Illumination Does Not Dim

Instrument Cluster and Panel Illumination

Pinpoint Tests

Pinpoint Test C: All Control Illumination Does Not Dim

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

Normal Operation

The Smart Junction Box (SJB) monitors the input from the instrument panel dimmer switch by sending a voltage reference signal through circuit VLN18 (BU/WH) to the instrument panel dimmer switch. The return signal is sent through circuit RLN29 (WH/OG) back to the SJB. Based on the input from the instrument panel dimmer switch, the SJB sends a Pulse Width Modulated (PWM) voltage signal to the dimmable illumination sources. If the SJB detects a concern with the circuitry to the instrument panel dimmer switch, the SJB defaults the backlighting to a full intensity level.

The SJB also sends a message over the network to the Audio Control Module (ACM), the HVAC module, and the Instrument Cluster (IC) to indicate the backlighting intensity level. If the receiving module receives invalid backlighting data from the SJB for 5 seconds or less, the receiving module defaults the backlighting to the last setting.

If the receiving module does not receive the backlighting status message from the SJB or if the data received is deemed invalid for more than 5 seconds, the receiving module sets DTC U0140 in continuous memory (except the HVAC module) and defaults the backlighting to full nighttime intensity.

- DTC B2212 (Panel Dim Switch Out of Range) - an on-demand DTC that sets when the SJB detects an out of range condition on the dimmer input switch circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Instrument panel dimmer switch
- SJB

PINPOINT TEST C: ALL CONTROL 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.

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C1 CHECK THE EXTERIOR LIGHTING OPERATION

- Place the headlamp switch in each of its positions while observing the exterior lamps.
- Do the exterior lamps operate correctly?

Yes
GO to C2.

No
REFER to Lighting and Horns. Lighting and Horns

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C2 CHECK THE RECORDED RESULTS FROM BOTH CONTINUOUS AND ON-DEMAND SJB SELF-TESTS

- Check for recorded DTCs from the continuous and on-demand SJB self-tests.
- Is DTC B2212 present?

Yes
GO to C4.

No
GO to C3.

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C3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT

- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Monitor the SJB dimmer switch PID (DIM_SW_3) while rotating the instrument panel dimmer switch from the lowest setting to the highest setting.
- Does the PID indicate the switch is operating correctly?

Yes
GO to C9.

No
INSTALL a new instrument panel dimmer switch. REFER to Instrument Panel Dimmer Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.

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C4 CHECK CIRCUIT RLN29 (WH/OG) FOR A SHORT TO VOLTAGE

- Ignition OFF.
- Disconnect: SJB C2280b.
- Disconnect: Instrument Panel Dimmer Switch C2065.
- Ignition ON.
- Measure the voltage between the instrument panel dimmer switch C2065-4, circuit RLN29 (WH/OG), harness side and ground.

- Is any voltage present?

Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

No
GO to C5.

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C5 CHECK CIRCUIT VLN18 (BU/WH) FOR A SHORT TO VOLTAGE

- Measure the voltage between the instrument panel dimmer switch C2065-6, circuit VLN18 (BU/WH), harness side and ground.

- Is any voltage present?

Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

No
GO to C6.

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C6 CHECK CIRCUIT RLN29 (WH/OG) FOR AN OPEN OR A SHORT TO GROUND

- Ignition OFF.
- Measure the resistance between the instrument panel dimmer switch C2065-4, circuit RLN29 (WH/OG), harness side and the SJB C2280b-33, circuit RLN29 (WH/OG), harness side; and between the instrument panel dimmer switch C2065-4, circuit RLN29 (WH/OG), harness side and ground.

- Is the resistance less than 5 ohms between the instrument panel dimmer switch and the SJB, and greater than 10,000 ohms between the instrument panel dimmer switch and ground?

Yes
GO to C8.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

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C8 CHECK THE INSTRUMENT PANEL DIMMER SWITCH

- Carry out the component test for the instrument panel dimmer switch.

- Is the instrument panel dimmer switch OK?

Yes
GO to C9.

No
INSTALL a new instrument panel dimmer switch. REFER to Instrument Panel Dimmer Switch Service and Repair. TEST the system for normal operation.

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C9 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. 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.

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