The body control module (BCM) supplies battery voltage to the courtesy lamps through the courtesy lamps supply voltage circuit when the BCM is awake. When the BCM sees the proper inputs it will ground the courtesy lamps low control circuit, and the courtesy lights will illuminate.
The BCM must command the courtesy lamps ON.
The BCM stores DTC B21/31 in memory.
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: Interior Lights Schematics | |||
1 | Did you perform the Lighting System Diagnostic System Check? | Go to Step 2 | |
Does the test lamp illuminate? | Go to Diagnostic Aids | Go to Step 3 | |
Inspect the Courtesy Fuse for an open. Is the courtesy fuse open? | Go to Step 8 | Go to Step 4 | |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 9 | |
5 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 6 |
6 | Repair the open or high resistance in the courtesy lamps supply voltage circuit. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 11 | |
7 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 10 |
8 | Repair the short to ground in the battery positive voltage circuit of the BCM that feeds the courtesy lamps supply voltage circuit or the courtesy lamps supply voltage circuit. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 11 | -- |
9 | Repair the open or high resistance in the battery positive voltage circuit of the BCM that feeds the courtesy lamps supply voltage circuit. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 11 | -- |
10 |
ImportantPerform the set up procedure for the Body Control Module. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System. Replace the body control module. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 11 | -- |
11 |
Does the DTC reset? | Go to Step 2 | System OK |