GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The body control module (BCM) uses the courtesy lamps supply voltage circuit as a input circuit and a output circuit. When used as an output circuit the BCM provides battery power to the courtesy lamps. When used as a input circuit the BCM provides an interface to the electrical loads which are controlled by the BCM when the output is inactive. This will allow for determination of the ON/OFF status of the loads.

Conditions for Running the DTC

If the voltage level at the BCM drops to 0.

Conditions for Setting the DTC

    • The fault code sets when the BCM commanded state does not match the feedback. When the courtesy lamps supply voltage circuit is commanded high and a short to ground is present.
    • The fault code also sets when the battery positive voltage circuit of the BCM that is fed by the INADV Power Bus fuse is open or shorted to ground.
    • The condition above must be present for more than 0.1 seconds.

Action Taken When the DTC Sets

The BCM stores DTC B1482 in memory.

Conditions for Clearing the MIL/DTC

    • A current DTC B1482 will clear if voltage is present on the battery positive voltage circuit and the BCM does not detect a short to ground.
    • A history DTC B1482 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.
    • The BCM receives a clear code command from the scan tool.

Diagnostic Aids

    • If the DTC B1482 is a history DTC, 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 ground in the courtesy lamps supply voltage circuit .
       - An intermittent open in the battery positive voltage circuit of the BCM that is fed by the INADV Power Bus fuse.
       - The BCM is intermittently shorted to ground.

Test Description

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

  1. Checks the battery positive voltage circuit at the BCM for an open or a short to ground.

  2. Checks the courtesy lamps supply voltage circuit for a short to ground. If the fuse in the jumper opens, there is a short to ground in the courtesy lamps supply voltage circuit.

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Inadvertent Power Input parameter in the Body Control Module data list.

Does the scan tool display ON?

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn the ignition to the OFF position.
  2. Disconnect the BCM C4 connector.
  3. Using a test lamp connected to ground, probe the battery positive voltage supply circuit of the BCM that is fed by the INADV Power Bus fuse.

Does the test lamp illuminate?

Go to Step 4

Go to Step 6

4

  1. Connect a 15-amp fused jumper between the battery positive voltage circuit and the courtesy lamps supply voltage circuit.
  2. Place the reading lamps switches in the on position.

Do the reading lamps operate

Go to Step 5

Go to Step 7

5

Inspect for poor connections at the harness connector 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 9

Go to Step 8

6

Repair an open or short to ground in the battery positive voltage circuit of the BCM that is fed by the INADV Power Bus fuse. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 9

--

7

Repair an open or a short to ground in the courtesy lamps supply voltage circuit of the BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 9

--

8

Important: Perform the setup procedure for the body control module (BCM). Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the body control module (BCM). Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 9

--

9

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK