Pinpoint Test A: All Dimmable Illumination Is Inoperative
Instrument Cluster and Panel Illumination
Pinpoint Tests
Pinpoint Test A: All Dimmable Illumination Is Inoperative
Refer to Wiring Diagram Set 71 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Cluster and Panel Illumination for schematic and connector information. Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) sends a voltage signal to the instrument panel dimmer switch. The signal is routed through a variable resistor within the instrument panel dimmer switch and then back to the SJB to an internal ground. The voltage signal changes depending on the position of the dimmer switch. When the dimmer switch is in the lowest setting, the resistance is low. When the SJB senses the voltage is low (switch in the lowest setting), the dimmable backlighting intensity is low. When the SJB senses the voltage reference is high (switch in the highest setting), the dimmable backlighting intensity is bright. If the signal is too high (an open circuit or short to voltage), the SJB faults the dimmable backlighting to full nighttime brightness. If the dimmer switch input circuit is short to ground, the SJB interprets this as the lowest setting and sets the backlighting to the lowest intensity level, appearing to be inoperative.
Based on input received from the instrument panel dimmer switch, the SJB sends a message over the network to the backlit modules indicating the backlighting intensity level and a Pulse Width Modulated (PWM) voltage to the hardwired dimmable illumination sources.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Instrument panel dimmer switch
- SJB
PINPOINT TEST A: ALL DIMMABLE ILLUMINATION IS INOPERATIVE
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.
- Are any DTCs recorded?
Yes
REFER to DTC Charts. Instrument Cluster and Panel Illumination
No
GO to A2.
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A2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH
- Ignition OFF.
- Disconnect: Instrument Panel Dimmer Switch C2065.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Do the dimmable components illuminate?
Yes
INSTALL a new instrument panel dimmer switch. REFER to Instrument Panel Dimmer Switch Service and Repair. TEST the system for normal operation.
No
GO to A3.
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A3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
- Place the headlamp switch in the OFF position.
- Disconnect: SJB C2280b.
- Measure the resistance between the instrument panel dimmer switch C2065-6, circuit VLN18 (BU/WH), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to A4.
No
REPAIR circuit VLN18 (BU/WH) for a short to ground. TEST the system for normal operation.
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A4 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. RUN the on-demand self-test (required to clear certain DTCs). CORRECT any unresolved DTCs. CLEAR all DTCs. TEST the system for normal operation.
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