Pinpoint Test O: The Ambient Lighting Does Not Cycle Through Brightness Settings
Interior Lighting
Pinpoint Tests
Pinpoint Test O: The Ambient Lighting Does Not Cycle Through Brightness Settings - MKZ
Refer to Wiring Diagram Set 89 (Fusion/Milan/MKZ, Fusion Hybrid/Milan Hybrid), Interior Lamps for schematic and connector information. Diagrams By Number
Normal Operation
The Interior Lighting Control Module (ILCM) sends 2 voltage reference signals to the ambient lighting dimmer switch (dim up or dim down). When the ambient lighting dimmer switch (a momentary contact switch) is pressed (dim up or dim down), the voltage signal is routed to the ground indicating a request for the module to cycle the ambient lighting to the next dim up or dim down setting.
- DTC B2B18 (Ambient Light Switch Input Fault) - a continuous and on-demand DTC that sets when the ILCM detects a short to ground from the ambient lighting dim up or dim down input circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Ambient lighting harness
- Ambient lighting dimmer switch
- ILCM
PINPOINT TEST O: THE AMBIENT LIGHTING DOES NOT CYCLE THROUGH BRIGHTNESS SETTINGS - MKZ
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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O1 CHECK THE INPUT FROM THE AMBIENT LIGHTING SWITCH
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- While pressing and releasing the ambient lighting dimmer switch up and down, monitor the ILCM ambient lighting dimmer switch PID (AmbiDim).
- Does the PID agree with the switch positions?
Yes
GO to O9.
No
If the PID indicates up or down with the switch not pressed, GO to O2.
If the PID indicates idle when the switch is pressed up or down, GO to O4.
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O2 CHECK THE AMBIENT LIGHTING DIMMER SWITCH FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Ambient Lighting Dimmer Switch C2305 .
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- Monitor the ILCM ambient lighting dimmer switch PID (AmbiDim).
- Does the PID still indicate up or down?
Yes
GO to O3.
No
INSTALL a new ambient lighting dimmer switch. REFER to Ambient Lighting Switch Service and Repair. TEST the system for normal operation.
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O3 CHECK THE AMBIENT LIGHTING DIMMER SWITCH INPUT CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: ILCM C2301 .
- Measure the resistance between the ILCM C2301-9, circuit CLN61 (WH/VT), harness side and ground; and between the ILCM C2301-19, circuit CLN62 (BN/BU), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to O9.
No
REPAIR the circuit in question for a short to ground. CLEAR the DTCs. REPEAT the self-test.
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O4 CHECK THE INPUT FROM THE AMBIENT LIGHTING DIMMER SWITCH DIM DOWN CIRCUIT
- Ignition OFF.
- Disconnect: Ambient Lighting Dimmer Switch C2305 .
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- Monitor the ILCM ambient lighting dimmer switch PID (AmbiDim).
- Connect and remove a fused jumper wire between the ambient lighting switch C2305-3, circuit CLN61 (WH/VT), harness side and ground.
- Does the PID indicate down?
Yes
GO to O6.
No
GO to O5.
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O5 CHECK THE AMBIENT LIGHTING DIMMER SWITCH DIM DOWN CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: ILCM C2301 .
- Measure the resistance between the ILCM C2301-19, circuit CLN61 (WH/VT), harness side and the ambient lighting dimmer switch C2305-3, circuit CLN61 (WH/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to O9.
No
REPAIR circuit CLN62 (BN/BU) for an open. TEST the system for normal operation.
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O6 CHECK THE INPUT FROM THE AMBIENT LIGHTING DIMMER SWITCH DIM UP CIRCUIT
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- Monitor the ILCM ambient lighting dimmer switch PID (AmbiDim).
- Connect a fused jumper wire between the ambient lighting dimmer switch C2305-7, circuit CLN62 (BN/BU), harness side and ground.
- Does the PID indicate up?
Yes
REMOVE the jumper wire. GO to O8.
No
REMOVE the jumper wire. GO to O7.
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O7 CHECK THE AMBIENT LIGHTING DIMMER SWITCH DIM UP CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: ILCM C2301 .
- Measure the resistance between the ILCM C2301-9, circuit CLN62 (BN/BU), harness side and the ambient lighting dimmer switch C2305-7, circuit CLN62 (BN/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to O9.
No
REPAIR circuit CLN61 (WH/VT) for an open. TEST the system for normal operation.
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O8 BYPASS THE AMBIENT LIGHTING DIMMER SWITCH
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- Monitor the ILCM ambient lighting dimmer switch PID (AmbiDim).
- Connect a fused jumper wire between the ambient lighting dimmer switch C2305-3, circuit CLN61 (WH/VT), harness side and the ambient lighting switch C2305-4, circuit GD908 (BK), harness side.
- Does the PID indicate down?
Yes
INSTALL a new ambient lighting dimmer. REFER to Ambient Lighting Switch Service and Repair. TEST the system for normal operation.
No
GO to O9.
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O9 CHECK FOR CORRECT ILCM OPERATION
- Disconnect the ILCM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the ILCM connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new ILCM. REFER to Interior Lighting Control Module (ILCM) Interior Lighting Control Module (ILCM). 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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