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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 G8 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Courtesy Lamps Malfunction

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.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

CTSY/TRN SIG RT FRT Fuse B+ Terminal 2 X4

B2615 00

B2615 00

--

--

INADV/PWR/LED Fuse B+ Terminal 2 X3

5

5

5

--

Courtesy Lamp Defeat Signal

4

4

4

--

Courtesy Lamps Control

B2615 00

B2615 00

B2615 00

--

Courtesy Lamp Defeat Ground

--

4

--

--

Dome/Reading Lamps Ground

--

2

--

--

Dome Lamp - Front Ground

--

1

--

--

Dome Lamp - Rear Ground

--

1

--

--

Ignition Key Cylinder Lamp Ground

--

1

--

--

Sunshade - Left Ground

--

3

--

--

Sunshade - Right Ground

--

3

--

--

Rear Compartment Courtesy Lamp Ground

--

6

--

--

1. Courtesy Lamps Malfunction

2. Dome Lamp Switch Malfunction

3. Sunshade Lamps Malfunction

4. Courtesy Lamp Defeat Malfunction

5. Reading Lamps Malfunction

6. Rear Compartment Lamp Malfunction

Circuit/System Description

The body control module (BCM) applies battery voltage to the courtesy lamps through 2 separately controlled courtesy lamp supply voltage circuits. When any door is opened, the door ajar switch contacts close and the BCM receives a door-ajar input. If the BCM receives a door lock or unlock input or a rear hatch open input, the BCM will activate the courtesy lamp supply voltage circuits, providing battery voltage to all of the dome/reading lamps, ignition key cylinder lamp, rear compartment lamp and sunshade lamps. In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the courtesy lamp control circuits to prevent a total battery discharge condition.

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 Verification
  1. Ignition ON, doors CLOSED, observe the scan tool Ctsy. Lamp Actv. Reason parameter while turning the courtesy lamp defeat switch ON and OFF. The parameter should change between Off and Manual Defeat.
    2. ⇒If the parameter does not change between the commanded states, refer to Dome Lamp Defeat Switch Malfunction.
  2. Ignition ON, courtesy lamp defeat switch OFF, observe the scan tool Ctsy. Lamp Actv. Reason parameter while opening and closing each door. The parameter should change between Door Open and Off.
    3. ⇒If the parameter does not change as each door is opened and closed, refer to Door Ajar Indicator Malfunction.
  3. Operate the dome lamp switch On and Off. The dome lamps should turn On and Off as the switch is activated.
    4. ⇒If the dome lamps do not turn On and Off as the switch is activated, refer to Dome Lamp Switch Malfunction.
  4. Command the Courtesy Lamps ON and OFF with a scan tool. The courtesy lamps should turn ON and OFF when changing between the commanded states.
    5. ⇒If the courtesy lamps do not turn On and Off when commanded, refer to Courtesy Lamps Malfunction.

Circuit/System Testing

Dome Lamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the front dome lamp.
  2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the ground circuit terminal 1 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp does not illuminate between the signal circuit terminal 2 and ground.
    4. ⇒If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Test for B+ between the signal circuit terminal 2 and ground.
    5. ⇒If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the dome lamp.

Dome Lamp Defeat Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the front dome lamp.
  2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the ground circuit terminal 1 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp does not illuminate between the signal circuit terminal 3 and ground.
    4. ⇒If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Test for B+ between the signal circuit terminal 3 and ground.
    5. ⇒If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the dome lamp.

Courtesy Lamps Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative courtesy lamp.
  2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.
    3. • Dome/reading lamp - front terminal 1 - with CF5
    • Dome lamp - front terminal 1 - without CF5
    • Dome lamp - rear terminal 1
    • Ignition key cylinder lamp terminal B
    ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground.
    4. • Dome/reading lamp - front terminal 4 - with CF5
    • Dome lamp - front terminal 4 - without CF5
    • Dome lamp - rear terminal 2
    • Ignition key cylinder lamp terminal A
  4. Command the Courtesy Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    5. ⇒If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    ⇒If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the inoperative courtesy lamp.

Reading Lamps Malfunction - with CF5

  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
    3. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X3 harness connector at the BCM.
  4. Disconnect the harness connector at the inoperative dome/reading lamp assembly.
  5. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the ground circuit terminal 1 and ground.
    6. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 5 and ground.
    7. ⇒If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. Remove the INADV/PWR/LED fuse and verify the test lamp turns OFF.
    8. ⇒If the test lamp remains illuminated, test the control circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, replace the inoperative dome/reading lamp assembly.

Rear Compartment Courtesy lamp Malfunction

  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
    3. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X3 harness connector at the BCM.
  4. Disconnect the harness connector at the rear compartment courtesy lamp.
  5. Ignition OFF, trunk OPEN, test for less than 1 ohm between the control circuit terminal B and ground.
    6. ⇒If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the rear compartment lid latch.
  6. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A and ground.
    7. ⇒If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. Remove the INADV/PWR/LED fuse and verify the test lamp turns OFF.
    8. ⇒If the test lamp remains illuminated, test the control circuit terminal A for a short to voltage. If the circuit tests normal, replace the BCM.
  8. Ignition OFF, connect the harness connector at the rear compartment courtesy lamp. Disconnect the harness connector at the rear compartment lid latch.
  9. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 2 and ground.
    10. ⇒If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance.
  10. If all circuits test normal, replace the rear compartment courtesy lamp.

Sunshade Lamps Malfunction

  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
    3. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X3 harness connector at the BCM.
  4. Ignition OFF, disconnect the harness connector at the inoperative sunshade lamp.
  5. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the ground circuit terminal 1 and ground.
    6. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 2 and ground.
    7. ⇒If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. Remove the INADV/PWR/LED and verify the test lamp turns OFF.
    8. ⇒If the test lamp remains illuminated, test the control circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, replace the inoperative sunshade lamp assembly.

I/P Compartment Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the I/P compartment lamp.
  2. Ignition OFF, I/P compartment OPEN, test for less than 1 ohm between the control circuit terminal A and ground.
    3. ⇒If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the I/P compartment lamp switch.
  3. Ignition OFF, verify that a test lamp illuminates between the control circuit terminal B and ground.
    4. ⇒If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Remove the INADV/PWR/LED and verify the test lamp turns OFF.
    5. ⇒If the test lamp remains illuminated, test the control circuit terminal A for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the I/P compartment lamp.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Reading Lamp Replacement
    •  Ignition Lock Cylinder Bulb Replacement
    •  Dome Lamp Replacement
    •  Headlamp Switch Replacement
    •  Rear Compartment Courtesy Lamp Replacement
    •  Control Module References for BCM replacement, setup, and programming