Circuit Description
The body control module (BCM) receives a ground signal from the door jamb or courtesy lamp switches requesting courtesy lamp illumination. When this occurs, the BCM directly sends a voltage through the courtesy lamp supply voltage circuit illuminating the courtesy lamps.
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 shorted to voltage. |
| • | There is a loss of the rear fuse block TBC 3 battery supply voltage to the BCM for more than 1 second. |
Action Taken When the DTC Sets
The courtesy 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.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step test determines if an open or short to ground exists.
-
This step test determines if a short to ground exists in the lamp wiring or internally within the BCM.
-
This step test determines if an open exists in the TBC 3 battery positive voltage circuit, the courtesy lamp supply voltage circuit, or internally within the BCM.
-
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 | |
Inspect the TBC 3 fuse in the rear fuse block. Is the fuse good? | Go to Step 4 | Go to Step 3 | |
Test the TBC 3 battery positive voltage and courtesy lamp supply voltage 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 7 | Go to Step 5 | |
Test the TBC 3 battery positive voltage and courtesy lamp supply voltage circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 7 | Go to Step 5 | |
5 | Inspect for poor connections at the harness connectors of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 7 | Go to Step 6 |
|
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 7 | -- | |
7 |
Does the DTC reset? | Go to Step 2 | System OK |
