Circuit Description
The body control module (BCM) receives a ground signal from the door jamb, liftglass/liftgate if equipped, or courtesy lamp switches requesting courtesy/dome lamp illumination. When this occurs, the BCM directly sends a voltage through the courtesy lamp supply voltage circuit illuminating the courtesy/dome lamps.
Voltage for the courtesy lamp supply voltage circuit as well as the backup lamp supply voltage circuit is from the left instrument panel fuse block TBC 2B 15-amp fuse directly through the BCM to these circuits.
Conditions for Running the DTC
The battery voltage must be between 9.0-16.0 volts.
Conditions for Setting the DTC
| • | When the BCM receives a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is shorted to ground. |
| • | When the BCM is not receiving a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is open only to the first splice from the BCM or the circuit is shorted to voltage. |
| • | There is a loss of the instrument panel fuse block TBC 2B battery supply voltage to the BCM for 1 second. |
Action Taken When the DTC Sets
The courtesy dome lamps will not operate or are always ON.
Conditions for Clearing the MIL/DTC
| • | This DTC will clear on current status after the condition for setting the fault is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
| • | History and current DTCs can be cleared using a scan tool. |
Diagnostic Aids
| • | Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
| • | An open circuit up to the first splice only, from the BCM, will set the DTC. |
| • | A short to ground on the backup lamp supply voltage circuit, courtesy lamp supply voltage circuit OR the TBC 2B battery positive voltage circuit to the BCM will open the TBC 2B fuse in the left instrument panel fuse block. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step test determines if the problem exists in the wiring or the BCM.
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This step test determines if the problem exists in the wiring or the BCM.
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After replacement of the BCM you must calibrate the new module for proper operation.
Step | Action | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Interior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System | |||||||||||
1 | Did you perform the Lighting System Diagnostic System Check? | Go to Step 2 | |||||||||
2 | Inspect the TBC 2B fuse in the instrument panel fuse block. Is the fuse open? | Go to Step 3 | Go to Step 4 | ||||||||
Test the following circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems:
Did you find and correct the condition? | Go to Step 6 | Go to Step 5 | |||||||||
Test the courtesy lamp supply voltage circuit for the following conditions:
Did you find and correct the condition? | Go to Step 6 | Go to Step 5 | |||||||||
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Important: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 6 | -- | |||||||||
6 |
Does the DTC reset? | Go to Step 2 | System OK | ||||||||
