Pinpoint Test A: The Control Illumination Is Inoperative - All Hardwired Illumination

Instrument Cluster and Panel Illumination

Pinpoint Tests

Pinpoint Test A: The Control Illumination Is Inoperative - All Hardwired Illumination

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

Normal Operation

When the headlamp switch is placed in the PARKING or HEADLAMP ON position, the Smart Junction Box (SJB) supplies either a Pulse-Width Modulation (PWM) signal or 12 volts to the various backlighting sources in the instrument panel, doors and console.

- DTC B2027 (LED Backlighting Output Circuit Failure) - is a continuous and on-demand DTC that sets when the SJB detects a short to ground on the dimmable backlighting circuits.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- SJB



PINPOINT TEST A: THE CONTROL ILLUMINATION IS INOPERATIVE - ALL HARDWIRED ILLUMINATION

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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A1 CHECK FOR RECORDED SJB DTCs FROM THE ON-DEMAND SELF-TEST


- Use the recorded results from the SJB self-test.
- Is DTC B2027 recorded?

Yes
GO to A3.

No
GO to A2.

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A2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Monitor the SJB instrument panel dimmer switch PID (PANELINT) 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
INSTALL a new SJB. TEST the system for normal operation.

No
INSTALL a new instrument panel dimmer switch. CLEAR the DTCs. REPEAT the self-test.

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A3 CHECK CIRCUITS 1403 (BK/WH), 19 (LB/RD), 293 (OG/RD), 203 (OG/LB), 2023 (YE/LB), 2029 (LB/WH), 2030 (YE/WH) AND 1425 (GY/WH) FOR A SHORT TO GROUND


- Ignition OFF.
- Disconnect: SJB C2280b.
- Disconnect: SJB C2280e.
- Disconnect: SJB C2280f.
- Connect a fused jumper wire between the SJB connector and battery positive as follows:





- Did the jumper wire fail on any of the circuits?

Yes
REMOVE the jumper wire. REPAIR the circuit in question for a short to ground. CLEAR the DTCs. REPEAT the self-test.

No
REMOVE the jumper wire. INSTALL a new SJB. TEST the system for normal operation.

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