Pinpoint Test M: The Ambient Lighting Is Inoperative
Interior Lighting
Pinpoint Test M: The Ambient Lighting Is Inoperative
Refer to Wiring Diagram Set 89, Interior Lamps for schematic and connector information. Diagrams By Number
Normal Operation
The Interior Lighting Control Module (ILCM) supplies voltage and ground to the LEDs located in the floor console cup holders, storage tray, storage bin, inside door handles and map pockets and the front and rear footwells. The ILCM turns the ambient lighting on to a pre-set color (white) and brightness setting when a door/liftgate is open or the illuminated entry/exit feature is active. The ambient lighting is also active when the ignition is in the RUN mode and the parking lamps are on.
The ambient lighting switch is used to cycle through the 7 color combinations or to turn the ambient lighting feature off. There are 4 different color (red, blue, green and white) LEDs housed within each LED assembly.
The ILCM sends a voltage signal to the ambient lighting switch. When the ambient lighting switch (a momentary contact switch) is pressed to cycle the color setting, the voltage signal is routed to ground, indicating a request for the module to cycle the ambient lighting to the next color setting or to turn the ambient lighting off.
The ambient lighting dimmer switch is used to decrease or increase the lighting intensity.
The color and brightness settings can only be changed when the ignition is in the RUN mode, the parking lamps are on, the liftgate and all the doors are closed.
- 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 switch input circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Ambient lighting harness
- Ambient lighting switch
- ILCM
PINPOINT TEST M: THE AMBIENT LIGHTING 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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M1 CHECK FOR COMMUNICATION TO THE ILCM
- Carry out the network test using the scan tool.
- Does the ILCM respond to the scan tool?
Yes
GO to M2.
No
REFER to Module Communications Network Testing and Inspection.
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M2 CHECK THE INPUT FROM THE AMBIENT LIGHTING SWITCH
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- While pressing and releasing the ambient lighting switch, monitor the ILCM ambient lighting switch PID (AmbiColor).
- Does the PID read active with the switch pressed and idle with the switch released?
Yes
GO to M8.
No
If the PID always reads active, GO to M3.
If the PID always reads idle, GO to M5.
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M3 CHECK THE AMBIENT LIGHTING SWITCH FOR A SHORT TO GROUND
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- Disconnect: Ambient Lighting Switch C2306 .
- Monitor the ILCM ambient lighting switch PID (AmbiColor).
- Does the PID still read active?
Yes
GO to M4.
No
INSTALL a new ambient lighting switch. REFER to Ambient Lighting Switch Service and Repair. TEST the system for normal operation.
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M4 CHECK THE AMBIENT LIGHTING SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: ILCM C3256 .
- Measure the resistance between the ILCM C3256-8, circuit CLN60 (WH/BN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to M9.
No
REPAIR circuit CLN60 (WH/BN) for a short to ground. TEST the system for normal operation.
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M5 BYPASS THE AMBIENT LIGHTING SWITCH
- Ignition OFF.
- Disconnect: Ambient Lighting Switch C2306 .
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- Monitor the ILCM ambient lighting switch PID (AmbiColor).
- Connect a fused jumper wire between the ambient lighting switch C2306-2, circuit CPL60 (WH/BN), harness side and ground.
- Does the PID read active?
Yes
REMOVE the jumper wire. GO to M6.
No
REMOVE the jumper wire. GO to M7.
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M6 BYPASS THE AMBIENT LIGHTING SWITCH USING THE CONNECTOR GROUND
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- Monitor the ILCM ambient lighting switch PID (AmbiColor).
- Connect a fused jumper wire between the ambient lighting switch C2306-2, circuit CLN60 (BN/YE), harness side and the ambient lighting switch C2306-6, circuit GD116 (BK/VT), harness side.
- Does the PID read active?
Yes
REMOVE the jumper wire. INSTALL a new ambient lighting switch. REFER to Ambient Lighting Switch Service and Repair. TEST the system for normal operation.
No
REMOVE the jumper wire. REPAIR circuit GD116 (BK/VT) for an open. TEST the system for normal operation.
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M7 CHECK THE AMBIENT LIGHTING SWITCH INPUT CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: ILCM C3256 .
- Measure the resistance between the ILCM C3256-8, circuit CLN60 (BN/YE), harness side and the ambient lighting switch C2306-2, circuit CLN60 (BN/YE), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to M9.
No
REPAIR circuit CLN60 (WH/BN) for an open. TEST the system for normal operation.
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M8 CHECK THE AMBIENT LIGHTING RETURN CIRCUIT FOR AN OPEN
- Ignition OFF.
- Check the diode circuits between the ILCM connector, harness side as follows:
- Does the meter indicate the circuit is good?
Yes
GO to M9.
No
REPAIR circuit RLN44 (BN) for an open. TEST the system for normal operation.
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M9 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) 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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