GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B1480 00: Battery Rundown Protection

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Inadvertent Power Courtesy Lamp

B1480

1, 2, 3, 4

--

--

Ground

--

1, 2, 3, 4

--

--

1. I/P Compartment Lamp Inoperative

2. Reading Lamp Inoperative

3. Rear Compartment Lamp Inoperative

4. Vanity Mirror Lamp Inoperative

Circuit/System Description

Battery voltage is supplied at all times to the body control module (BCM) from the 10A INT LAMPS fuse located in the rear fuse block. The BCM then applies this voltage to the following lamps:

-V4U Base Vehicle

    • Instrument panel (I/P) compartment lamp
    • Courtesy lamp module
    • Rear compartment lamp
    • Vanity mirror lamps

+V4U Limousine

    • I/P compartment lamp
    • Rear compartment lamp
    • Vanity mirror lamps

+V4U/B9Q Hearse

    • I/P compartment lamp
    • Overhead console lamps
    • Overhead lamp relay
    • Rear compartment lamp
    • Rear roof rail lamps
    • Vanity mirror lamps

In the event that any of these lamps were to remain illuminated for more the 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power courtesy lamps circuit to prevent total battery discharge.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The BCM detects a short to ground on the inadvertent power courtesy lamp circuit.

Action Taken When the DTC Sets

The BCM will deactivate inadvertent power to the courtesy lamps.

Conditions for Clearing the DTC

    • The conditions for setting the DTC are no longer present.
    • A history DTC clears after 100 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Interior Lights Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Ignition ON, activate each inadvertent power courtesy lamp. Ignition OFF, activate each inadvertent power courtesy lamp. Lamps should remain illuminated for more the 20 minutes with the ignition switch in the OFF position. The BCM will deactivate the inadvertent power courtesy lamps circuit to prevent total battery discharge.

Circuit/System Testing

  1. Ignition OFF, disconnect the appropriate harness connector at each component fed by the inadvertent power courtesy lamp circuit.
  2. Ignition ON, with a scan tool clear the DTC.
  3. Operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset.
  4. If the DTC resets, test the inadvertent power courtesy lamp circuit for a short to ground. If the circuit test normal, replace the BCM.
  5. Connect each component one at a time and verify that the DTC does not reset as current.
  6. If the DTC resets, test or replace the component responsible for setting the DTC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Instrument Panel Compartment Lamp Switch Replacement
    •  Instrument Panel Storage Compartment Lamp Replacement
    •  Roof Rail Rear Courtesy Lamp Switch Replacement
    •  Roof Rail Rear Courtesy Lamp Replacement
    •  Vanity Mirror Lamp Replacement
    •  Rear Compartment Courtesy Lamp Replacement
    •  Relay Replacement
    •  Control Module References for BCM replacement, setup, and programming