Pinpoint Test N: The Ambient Lighting Does Not Cycle Through Brightness Settings

Interior Lighting

Pinpoint Tests

Pinpoint Test N: The Ambient Lighting Does Not Cycle Through Brightness Settings

Refer to Wiring Diagram Set 89, Interior Lamps for schematic and connector information. Diagrams By Number

Normal Operation

The Interior Lighting Control Module (ILCM) sends a reference signal to the ambient light switch to monitor for a request to change the brightness level. When the switch for the brightness level is pressed, the signal is routed to ground indicating a request to change the brightness level to the next setting.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Ambient lighting harness
- Ambient lighting switch
- ILCM



PINPOINT TEST N: THE AMBIENT LIGHTING DOES NOT CYCLE THROUGH BRIGHTNESS SETTINGS

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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N1 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 switch, monitor the ILCM ambient lighting switch PID (AmbiDim).
- Does the PID agree with the switch positions?

Yes
GO to N6.

No
If the PID indicates active with the switch not pressed, GO to N2.
If the PID indicates idle when the switch is pressed, GO to N4.

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N2 CHECK THE AMBIENT LIGHTING SWITCH FOR A SHORT TO GROUND


- Ignition OFF.
- Disconnect: Ambient Lighting Switch C2304 .
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- Monitor the ILCM ambient lighting switch PID (AmbiDim).
- Does the PID still read active?

Yes
GO to N3.

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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N3 CHECK THE AMBIENT LIGHTING SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND


- Ignition OFF.
- Disconnect: ILCM C2411 .
- Measure the resistance between the ILCM C2411-9, circuit CLN55 (YE/VT), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to N6.

No
REPAIR circuit CLN55 (YE/VT) for a short to ground. CLEAR the DTCs. REPEAT the self-test.

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N4 CHECK THE AMBIENT LIGHTING SWITCH INPUT AND GROUND CIRCUIT FOR AN OPEN


- Ignition OFF.
- Disconnect: ILCM C2411 .
- Disconnect: Ambient Lighting Switch C2304 .
- Measure the resistance between the ambient lighting switch C2304-3, circuit CLN55 (YE/VT), harness side and the ILCM C2411-9, circuit CLN55 (YE/VT), harness side; and between the ambient lighting switch C2304-4, circuit GD114 (BK/BU), harness side and ground.




- Are the resistances less than 5 ohms?

Yes
GO to N5.

No
REPAIR circuit CLN55 (YE/VT) or circuit GD114 (BK/BU) for an open. TEST the system for normal operation.

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N5 BYPASS THE AMBIENT LIGHTING SWITCH


- Connect: ILCM C2411 .
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: ILCM DataLogger .
- Monitor the ILCM ambient lighting switch PID (AmbiDim).
- Connect and remove a fused jumper wire between the ambient lighting switch C2304-3, circuit CLN55 (YE/VT), harness side and the ambient lighting switch C2304-4, circuit GD114 (BK/BU), harness side.




- Does the PID indicate 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. GO to N6.

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N6 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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