Circuit Description
The body control module (BCM) receives a ground signal from a door jamb or cargo lamp switch requesting cargo lamp illumination. When this occurs, the BCM directly sends a voltage through the courtesy lamp supply voltage circuit illuminating the cargo lamp.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B2562 Cargo Lamp Control Circuit Low |
| • | DTC B2563 Cargo Lamp Control Circuit High |
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
| • | When the BCM receives a cargo lamp illumination request signal and the courtesy lamp supply voltage circuit is shorted to ground |
| • | When the BCM is not receiving a cargo lamp illumination request signal and the courtesy lamp supply voltage circuit is shorted to voltage |
| • | There is a loss of the underhood fuse block truck body controller (TBC) battery supply voltage to the BCM for more than 1 second. |
Action Taken When the DTC Sets
The cargo lamp will not operate or is 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 .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if the problem exists in the wiring.
-
This step determines if a condition exist in the TBC battery voltage supply circuit.
-
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 Data Communication Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Test the courtesy lamp supply voltage circuit for a short to voltage or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 6 | Go to Step 3 | |
Test the truck body controller (TBC) battery positive supply voltage circuit for a short to ground, open, or high resistance. Refer to Circuit Testing . Did you find and correct the condition? | Go to Step 6 | Go to Step 4 | |
4 | 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 . Did you find and correct the condition? | Go to Step 6 | Go to Step 5 |
Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 6 | -- | |
6 |
Does the DTC reset? | Go to Step 2 | System OK |
