GM Service Manual Online
For 1990-2009 cars only

Circuit Description

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.

Conditions for Running the DTC

The BCM must command the courtesy lamps ON.

Conditions for Setting the DTC

    • The BCM detects a high when the state should be low in the courtesy lamps low control circuit.
    • The condition above must be present for more than 0.3 seconds.

Action Taken When the DTC Sets

The BCM stores DTC B 22/32 in memory.

Conditions for Clearing the DTC

    • A current DTC B22/32 will clear if the short to battery in the courtesy lamps low control circuit is no longer detected by the BCM.
    • A history DTC B22/32 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present nor any other malfunction in the BCM is detected.

Diagnostic Aids

    • If the DTC B22/32 is a history DTC (B32), the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • The following conditions may cause an intermittent malfunction to occur:
       - An intermittent short to battery positive voltage in the courtesy lamps low control circuit
       - The courtesy lamps could intermittently be shorted to battery positive voltage.
       - The BCM is intermittently shorted to battery positive voltage.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Verifies that the fault is current.

  2. Tests for a short to battery voltage on the courtesy lamps low control circuit.

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the IP dimmer switch to the DOME position.

Do the courtesy lamps illuminate?

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn Off the ignition.
  2. Disconnect the BCM connectors C2 and C3.
  3. Turn ON the ignition, with the engine Off.
  4. Probe the courtesy lamps low control circuit of the BCM connector with a test lamp that is connected to ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 4

4

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 7

Go to Step 6

5

Repair the short to battery voltage in the courtesy lamps low control circuit. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 7

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6

Important: Perform 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 7

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7

  1. Clear the DTC. Refer to On-Board Diagnostic Features in Body Control System.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
  3. Retrieve the DTCs. Refer to On-Board Diagnostic Features in Body Control System.

Does the DTC reset?

Go to Step 2

System OK