Pinpoint Test I: The Courtesy Lamps Are Inoperative - From The Instrument Panel Dimmer Switch

Interior Lighting

Pinpoint Test I: The Courtesy Lamps Are Inoperative - From The Instrument Panel Dimmer Switch

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 on circuit 1034 (BK/WH) to determine if the courtesy lamps are requested. Based on the instrument panel dimmer switch status, the LCM energizes the interior lamps through circuit 53 (BK/LB).

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Instrument panel dimmer switch
- LCM



PINPOINT TEST I: THE COURTESY LAMPS ARE INOPERATIVE - FROM THE INSTRUMENT PANEL DIMMER SWITCH

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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I1 CHECK THE INSTRUMENT PANEL DIMMER SWITCH


- Ignition OFF.
- Disconnect: Instrument Panel Dimmer Switch C205b.
- Connect a fused jumper wire between the instrument panel dimmer switch C205b-5, circuit 1034 (BK/WH), harness side and the instrument panel dimmer switch C205b-4, circuit 57 (BK), harness side.




- Do the interior lamps illuminate?

Yes
REMOVE the jumper wire. INSTALL a new instrument panel dimmer switch. TEST the system for normal operation.

No
REMOVE the jumper wire. GO to I2.

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I2 CHECK CIRCUIT 57 (BK) FOR AN OPEN


- Disconnect: Negative Battery Cable.
- Measure the resistance between the instrument panel dimmer switch C205b-4, circuit 57 (BK), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
GO to I3.

No
REPAIR the circuit. TEST the system for normal operation.

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I3 CHECK CIRCUIT 1034 (BK/WH) FOR AN OPEN


- Disconnect: LCM C2145b.
- Measure the resistance between the LCM C2145b-3, circuit 1034 (BK/WH), harness side and the instrument panel dimmer switch C205b-5, circuit 1034 (BK/WH), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to I4.

No
REPAIR the circuit. TEST the system for normal operation.

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I4 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. 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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