Pinpoint Test A: All Dimmable Illumination Does Not Dim/Increase Brightness
Instrument Cluster and Panel Illumination
Pinpoint Test A: All Dimmable Illumination Does Not Dim/Increase Brightness
Refer to Wiring Diagram Set 71 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), 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 to monitor a request to turn up the dimmable lighting, turn down the dimmable lighting and to turn the courtesy lamps on or off. When the instrument panel dimmer switch is placed in the first detent up or down, the corresponding input signal is routed to ground indicating a request to turn the dimmable lighting up or down. 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 dimmer up or dimmer down input circuit. The SJB needs a dimmer 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.
When the parking lamps or headlamps are ON, the Smart Junction Box (SJB) monitors the input from the instrument panel dimmer switch to increase or decrease the dimmable lighting intensity.
If the dim up/dim down or the dome lamp request input circuit is shorted to ground for longer than 17 seconds, the SJB defaults the backlighting to full nighttime brightness.
- DTC B213A (Digital Dimmer Switch Input Circuit Failure) - a continuous and on-demand DTC that sets when the SJB detects a short to ground from the dimmer up, dimmer down or dome lamp on/off request input circuit.
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/INCREASE BRIGHTNESS
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 DTCs FROM THE SJB SELF-TEST
- Ignition OFF.
- Check the recorded DTCs from the SJB on-demand self-test.
- Is DTC B213A present?
Yes
GO to A2.
No
GO to A4.
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A2 REPEAT THE SJB SELF-TEST WITH THE INSTRUMENT PANEL DIMMER SWITCH DISCONNECTED
- 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 on-demand self-test.
- Is on-demand DTC B213A 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 INPUT CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB C2280b.
- Measure the resistance between the instrument panel dimmer switch , harness side and ground as follows:
- 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.
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A4 CHECK THE INSTRUMENT PANEL DIMMER SWITCH
- Disconnect: Instrument Panel Dimmer Switch C2065.
- 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 Service and Repair. TEST the system for normal operation.
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A5 CHECK THE INSTRUMENT PANEL DIMMER SWITCH DIM UP AND DIM DOWN INPUT CIRCUITS FOR VOLTAGE
- Ignition ON.
- Measure the voltage between the instrument panel dimmer switch C2065-7, circuit CLN12 (YE), harness side and ground; and between the instrument panel dimmer switch C2065-3, circuit CLN27 (WH/BN), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to A7.
No
GO to A6.
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A6 CHECK THE INSTRUMENT PANEL DIMMER SWITCH DIM UP AND DIM DOWN CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: SJB C2280b.
- Measure the resistance between the instrument panel dimmer switch C2065-7, circuit CLN12 (YE), harness side and the SJB C2280b-28, circuit CLN12 (YE), harness side.
- Measure the resistance between the instrument panel dimmer switch C2065-3, circuit CLN27 (WH/BN), harness side and the SJB C2280b-36, circuit CLN27 (WH/BN), 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.
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A7 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT AND RETURN CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: SJB C2280b.
- Ignition ON.
- Measure the voltage between the instrument panel dimmer switch , harness side and ground as follows:
- 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.
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A8 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR AN OPEN
- 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.
- Is the resistance less than 5 ohms?
Yes
GO to A9.
No
REPAIR circuit CLN27 (WH/BN) for an open. TEST the system for normal operation.
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A9 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 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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