Pinpoint Test A: The Courtesy Lamps Are Inoperative

Interior Lighting

Pinpoint Tests

Pinpoint Test A: The Courtesy Lamps Are Inoperative

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

Normal Operation

The Lighting Control Module (LCM) monitors the instrument panel dimmer switch status to determine if the courtesy lamps are requested. Based on the instrument panel dimmer switch status, the LCM energizes the interior lamps.

Fuse 18 (15A) in the Central Junction Box (CJB) provides power to the LCM. The Driver Door Module (DDM) monitors the LH front door ajar switch. The door ajar switches provide a path for ground supplied through the ajar switches, indicating an open door. The DDM then sends a message over the Standard Corporate Protocol (SCP) to command the LCM to supply power to the courtesy lamps.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- LCM

PINPOINT TEST A: THE COURTESY LAMPS ARE INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: The LCM may be configured for a police vehicle. In the police configuration, the LCM ignores the door ajar switch inputs for interior lighting. Check the LCM for correct configuration before continuing diagnostics.

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A1 CHECK THE DRIVER DOOR AJAR INPUT


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DDM DataLogger.
- Monitor the DDM driver door PIDs (D_DR_SW and P_DR_SW) while opening and closing the doors.
- Do the DDM PID values agree with the door positions?

Yes
GO to A2.

No
GO to Pinpoint Test D. Pinpoint Test D: The Courtesy Lamps Do Not Turn On With One Door Open

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A2 CHECK THE LCM VOLTAGE SUPPLY CIRCUIT FOR AN OPEN


- Ignition OFF.
- Disconnect: LCM C2145c.
- Measure the voltage between the LCM C2145c-4, circuit 54 (LG/YE), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to A3.

No
VERIFY the CJB fuse 18 (15A) is OK. If OK, REPAIR circuit 54 (LG/YE) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number

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A3 BYPASS THE LCM


- NOTE: If the fuse fails, repair circuit 53 (BK/LB) for a short to ground.

- Connect a fused jumper wire between the LCM C2145c-4, circuit 54 (LG/YE), harness side and the LCM C2145c-5, circuit 53 (BK/LB), harness side.




- Do the interior lamps illuminate?

Yes
REMOVE the jumper wire. GO to A4.

No
REMOVE the jumper wire. REPAIR circuit 53 (BK/LB) for an open. TEST the system for normal operation.

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A4 CHECK FOR CORRECT LCM OPERATION


- Disconnect all the LCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the LCM 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 LCM. 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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