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 B3801 00: Passenger Compartment Lamp Request Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Dome/Reading Lamp Control

B2615 00

B2615 00

B2615 00

--

Dome/Reading Lamp Supply Voltage

1

1

--

--

Dome Lamp Switch Signal

2

2

2

--

Exterior Lamps Illumination Supply Voltage

3

3

3

--

I/P Dimmer Switch Ground

--

2

--

--

LH Vanity Mirror Courtesy Lamp Ground

--

4

--

--

Overhead Console Courtesy/Reading Lamp Ground

--

4

--

--

Rear Dome Lamp Ground

--

1

--

--

RH Vanity Mirror Courtesy Lamp Ground

--

4

--

--

  1. Courtesy Lamps Malfunction
  2. Dome Lamp Switch Malfunction
  3. Exterior Lamps Malfunction
  4. Reading/Vanity Mirror Lamps Malfunction

Circuit/System Description

The body control module (BCM) monitors the courtesy lamp switch signal circuit in order to determine when the courtesy/dome lamps should be illuminated. When the BCM senses that the courtesy lamp switch signal circuit is grounded when the switch is activated, the BCM will directly illuminate the courtesy/dome lamps.

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

The BCM detects the courtesy lamp switch is active while the IP lamp dimmer switch at the dim position.

Action Taken When the DTC Sets

The courtesy/dome lamps will be inoperative.

Conditions for Clearing the 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.

Reference Information

Schematic Reference

Interior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

Dimmer Switch Circuit Test

  1. Ignition OFF, disconnect the harness connector at the IP dimmer switch.
  2. Test for less than 5.0 ohms between the low reference circuit terminal 10 and ground.
  3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool Dimming Input parameter is less than 1.0 volt.
  5. If greater than the specified range, test the signal circuit terminal 8 for a short to voltage. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, replace the IP dimmer switch.

Courtesy Lamp Switch Circuit Test

  1. Ignition OFF, disconnect the harness connector at the IP dimmer switch.
  2. Ignition ON, verify the scan tool Courtesy Lamp Switch parameter is Inactive.
  3. If not the specified value, test the signal circuit terminal 9 for a short to ground. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the IP dimmer switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Instrument Panel Lamp Dimmer Switch Replacement
    •  Control Module References for BCM replacement, programming, and setup