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 |
|---|---|---|---|---|
Body Control Module (BCM) VB2 Fuse B+ Terminal 2 X3 | 1 | 1 | -- | -- |
Body Control Module (BCM) VB5 Fuse B+ Terminal 2 X4 | 1 | 1 | -- | -- |
Courtesy Lamp Defeat Switch Signal | 4 | 4 | 4 | -- |
Courtesy Lamp Control | 1 | 1 | -- | -- |
Underseat Light Control | 5 | 5 | 5 | -- |
Courtesy Lamp Defeat Ground | -- | 4 | -- | -- |
Courtesy Lamp - Left Front Door Ground | -- | 1 | -- | -- |
Courtesy Lamp - Right Front Door Ground | -- | 1 | -- | -- |
Courtesy/Reading Lamps - Second Row Ground | -- | 1 | -- | -- |
Dome Lamp Ground | -- | 1 | -- | -- |
I/P Compartment Lamp Switch Ground | -- | 1 | -- | -- |
Ignition Switch Ground | -- | 1 | -- | -- |
Sunshade Lamp - Left Ground | -- | 3 | -- | -- |
Sunshade Lamp - Right Ground | -- | 3 | -- | -- |
Rear Compartment Courtesy Lamp Ground - Left | -- | 5 | -- | -- |
Rear Compartment Courtesy Lamp Ground - Right | -- | 1 | -- | -- |
Underseat Light - Driver | -- | 5 | -- | -- |
Underseat Light - Passenger | -- | 5 | -- | -- |
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Sunshade Lamps Malfunction 4. Courtesy Lamp Defeat Malfunction 5. Underseat Light 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 instrument panel (I/P) courtesy lamps, dome lamps, rearview mirror lamps, and rear compartment 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
Connector End View Reference
Description and Operation
Interior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- 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.
- 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.
| ⇒ | If the parameter does not change between the commanded states, refer to Courtesy Lamp Defeat Switch Malfunction. |
| ⇒ | If the parameter changes between the commanded states, refer to Courtesy Lamps Malfunction. |
| ⇒ | If the parameter does not change as each door is opened and closed, refer to Door Ajar Indicator Malfunction. |
Circuit/System Testing
Courtesy Lamp Defeat Switch Malfunction
- Ignition OFF, disconnect the harness connector at the front dome lamp.
- Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the ground circuit terminal 4 and ground.
- Ignition ON, all doors CLOSED, verify the scan tool Ctsy. Lamp Actv. Reason parameter is Off.
- Install a 3A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Ctsy. Lamp Actv. Reason parameter is Manual Defeat.
- If all circuits test normal, replace the courtesy lamp defeat switch.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. |
Courtesy Lamps Malfunction
- Ignition OFF, disconnect the harness connector at the inoperative courtesy lamp.
- 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.
- Connect a test lamp between the appropriate control circuit terminal listed below and ground.
- Command the Courtesy Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, replace the inoperative courtesy lamp.
| • | Courtesy lamp - left front door terminal 2 |
| • | Courtesy lamp - right front door terminal 2 |
| • | Courtesy/reading lamp 2nd row terminal B - with UUC |
| • | Courtesy/reading lamp 2nd row terminal 2 - without UUC |
| • | Front dome lamp terminal 4 |
| • | Ignition key lamp terminal F |
| • | I/P compartment lamp terminal 1 |
| • | Rear compartment courtesy lamp - left terminal 1 |
| • | Rear compartment courtesy lamp - right terminal 1 |
| • | Sunshade - left terminal B |
| • | Sunshade - right terminal B |
| ⇒ | If greater than the specified range, test the appropriate ground circuit for an open/high resistance. |
| • | Courtesy lamp - left front door terminal 1 |
| • | Courtesy lamp - right front door terminal 1 |
| • | Courtesy/reading lamp 2nd row terminal C - with UUC |
| • | Courtesy/reading lamp 2nd row terminal 3 - without UUC |
| • | Front dome lamp terminal 3 |
| • | Ignition key lamp terminal E |
| • | I/P compartment lamp terminal 2 |
| • | Rear compartment courtesy lamp - left terminal 2 |
| • | Rear compartment courtesy lamp - right terminal 2 |
| • | Sunshade - left terminal A |
| • | Sunshade - right terminal A |
| ⇒ | 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. |
Reading Lamps Malfunction
- Ignition OFF, disconnect the harness connector at the inoperative courtesy/reading lamp assembly.
- 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.
- Ignition ON, verify that a test lamp illuminates between the appropriate control circuit terminal listed below and ground.
- Remove the BCM VB2 fuse and verify the test lamp turns OFF.
- If all circuits test normal, replace the inoperative courtesy/reading lamp assembly.
| • | Courtesy/reading lamp 2nd row terminal B - with UUC |
| • | Courtesy/reading lamp 2nd row terminal 2 - without UUC |
| • | Front dome lamp terminal 4 |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| • | Courtesy/reading lamp 2nd row terminal A - with UUC |
| • | Courtesy/reading lamp 2nd row terminal 4 - without UUC |
| • | Front dome lamp terminal 3 |
| ⇒ | 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. |
| ⇒ | If the test lamp remains illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
Underseat lamp Malfunction
- Ignition OFF, disconnect the harness connector at the inoperative underseat lamp.
- Ignition OFF, test for less than 5 ohms between the ground circuit terminal D and ground.
- Ignition ON, park lamps ON, verify that a test lamp illuminates between the control circuit terminal B and ground.
- Verify that a test lamp illuminates between the control circuit terminal C and ground.
- Ignition ON, park lamps OFF, verify that a test lamp does not illuminate between the control circuit terminal B and ground.
- Verify that a test lamp does not illuminate between the control circuit terminal C and ground.
- If all circuits test normal, replace the inoperative underseat lamp.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | 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 headlamp switch. |
| ⇒ | 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 headlamp. |
| ⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp switch. |
| ⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
