Pinpoint Test A: All Dimmable Illumination Does Not Dim
Instrument Cluster and Panel Illumination
Pinpoint Tests
Pinpoint Test A: All Dimmable 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) sends voltage signals to the instrument panel dimmer switch (one for dim up and one for dim down). 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. When the switch is pressed to the first detent (either up or down), the corresponding voltage signal is routed back to the SJB to an internal ground indicating a request to increase or decrease the backlighting intensity. The SJB retains the last brightness setting between uses.
The instrument panel dimmer switch is a momentary contact switch.
- DTC B1685 (Lamp Dome Input Circuit Failure) - an on-demand DTC that sets when the SJB detects a short to ground from the dimmer up or dimmer down input circuit.
- DTC B1688 (Dome Lamp Input Circuit Short To Ground) - an on-demand DTC that sets when the SJB detects a short to ground from the dome lamp request input circuit.
- DTC B213A (Digital Dimmer Switch Input Circuit Failure) - a continuous and on-demand DTC that sets when the SJB detects multiple inputs active from the dimmer switch input circuits (dim up, dim down and/or dome lamp request).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Instrument panel dimmer switch
- SJB
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.
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A1 CHECK THE RECORDED RESULTS FROM THE SJB ON-DEMAND SELF-TEST
- Ignition OFF.
- Review the recorded results from the SJB on-demand self-test.
- Is DTC B1685, B1688 or B213A present?
Yes
GO to A2.
No
GO to A6.
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A2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH
- Disconnect: Instrument Panel Dimmer Switch C2065.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB Self-Test.
- Clear the DTCs and repeat the SJB self-test.
- Is the DTC still present?
Yes
GO to A3.
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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A3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH DIM DOWN CIRCUIT FOR A SHORT TO GROUND
- Disconnect: SJB C2280b.
- Measure the resistance between the instrument panel dimmer switch C2065-7, circuit CLN56 (BN/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to A4.
No
REPAIR circuit CLN56 (BN/VT) for a short to ground. TEST the system for normal operation.
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A4 CHECK THE INSTRUMENT PANEL DIMMER SWITCH DIM UP CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between the instrument panel dimmer switch C2065-3, circuit CLN55 (YE/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to A5.
No
REPAIR circuit CLN55 (YE/VT) for a short to ground. TEST the system for normal operation.
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A5 CHECK THE DOME LAMP REQUEST INPUT CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between the instrument panel dimmer switch C2065-2, circuit CLN28 (GN/BU), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to A12.
No
REPAIR circuit CLN28 (GN/BU) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
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A6 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280b.
- 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 circuit RLN29 (WH/OG) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to A7.
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A7 CHECK THE INSTRUMENT PANEL DIMMER SWITCH DIM DOWN CIRCUIT FOR A SHORT TO VOLTAGE
- Measure the voltage between the instrument panel dimmer switch C2065-7, circuit CLN56 (BN/VT), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit CLN56 (BN/VT) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to A8.
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A8 CHECK THE INSTRUMENT PANEL DIMMER SWITCH DIM UP CIRCUIT FOR A SHORT TO VOLTAGE
- Measure the voltage between the instrument panel dimmer switch C2065-3, circuit CLN55 (YE/VT), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit CLN55 (YE/VT) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to A9.
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A9 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR AN OPEN
- 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.
- Is the resistance less than 5 ohms?
Yes
GO to A10.
No
REPAIR circuit RLN29 (WH/OG) for an open. CLEAR the DTCs. REPEAT the self-test.
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A10 CHECK THE INSTRUMENT PANEL DIMMER SWITCH DIM DOWN CIRCUIT FOR AN OPEN
- Measure the resistance between the instrument panel dimmer switch C2065-7, circuit CLN56 (BN/VT), harness side and the SJB C2280b-36, circuit CLN56 (BN/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A11.
No
REPAIR circuit CLN56 (BN/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
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A11 CHECK THE INSTRUMENT PANEL DIMMER SWITCH DIM UP CIRCUIT FOR AN OPEN
- Measure the resistance between the instrument panel dimmer switch C2065-3, circuit CLN55 (YE/VT), harness side and the SJB C2280b-28, circuit CLN55 (YE/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A12.
No
REPAIR circuit CLN55 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
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A12 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. CLEAR the DTCs. REPEAT the self-test.
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