For 1990-2009 cars

### 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
--- | --- | --- | --- | ---
Courtesy Lamp Control - LF Door | 2 | 2 | 2 | --
Courtesy Lamp Control - RF Door | 2 | 2 | 2 | --
Cargo Lamp Control | B2570 00 | B2570 00 | 3 | --
Dome Light Control | 5 | 5 | 5 | --
Inadvertent Courtesy Lamp Control | B2652 02 | 5 | 5 | --
I/P Compartment Lamp Control | 1 | 1 | -- | --
Vanity Mirror Lamp - Left Control | 4 | 4 | -- | --
Vanity Mirror Lamp - Right Control | 4 | 4 | -- | --
Cargo Lamp Ground | -- | 3 | -- | --
Courtesy Lamp - LF Door Ground | -- | 2 | -- | --
Courtesy Lamp - RF Door Ground | -- | 2 | -- | --
Dome Lamp Ground | -- | 5 | -- | --
I/P Compartment Lamp Ground | -- | 1 | -- | --
Vanity Mirror Lamp - Right Ground | -- | 4 | -- | --
Vanity Mirror Lamp - Left Ground | -- | 4 | -- | --
1. Instrument Panel (I/P) Compartment Lamp Malfunction 2. Door Courtesy Lamps Malfunction 3. Cargo Lamp Malfunction 4. Vanity Mirror Lamps Malfunction 5. Dome/Reading Lamps Malfunction

### Circuit/System Description

The rear electrical center (REC) applies voltage to the cargo lamps and the I/P compartment lamp with individual control circuits. The REC applies voltage to the dome/reading lamps and the left and right vanity mirrors through the inadvertent courtesy lamp control circuit. In the event that the dome lamp, reading lamp, or vanity mirror lamp were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the REC will deactivate the inadvertent courtesy lamp control circuit to prevent battery discharge. When any door is opened, the jam switch contacts close and the REC receives a door-open input. If the REC receives a door lock or unlock input or a rear hatch open input, the REC will apply voltage to the individual courtesy lamp control circuits illuminating the courtesy lamps. The dome lamps will illuminate when a door is opened with the dome lamp switch in the DOOR position only.

### 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

#### Cargo Lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative cargo lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal 2 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal 1 and ground.
4. Command the Trunk Lamp Test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the REC.

⇒ | 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 REC.

5. If all circuits test normal, replace the inoperative cargo lamp.

#### Dome/Reading Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate dome lamp.
2. Ignition OFF, test for less than 5.0 ohms between the appropriate ground circuit terminal listed below and ground.

• | Dome lamp ground - front terminal 5

• | Dome lamp ground - center terminal 1

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify a test lamp illuminates between the appropriate control circuit terminal listed below and ground.

• | Dome lamp control - front terminal 6

• | Dome lamp control - center terminal 2

⇒ | 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 REC.

4. Connect a test lamp between B+ and the appropriate control circuit terminal listed below.

• | Dome lamp control - front terminal 7

• | Dome lamp control - center terminal 4

5. Command the Interior Lamp Test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the REC.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the REC.

6. If all circuits test normal, replace the appropriate dome lamp.

#### Door Courtesy Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative front door courtesy lamp.
2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal 3 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal 1 and ground.
4. Command the Interior Lamp Test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | 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 appropriate front door window switch.

⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the appropriate front door window switch.

5. If all circuits test normal, replace the inoperative front door courtesy lamp.

#### Instrument Panel (I/P) Compartment Lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the I/P compartment lamp.
2. Ignition OFF, test for less than 1.0 ohm between the ground circuit terminal 1 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 2 and ground.

⇒ | 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 REC.

4. If all circuits test normal, replace the I/P compartment lamp switch.

#### Vanity Mirror Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative vanity mirror.
2. Ignition OFF, scan tool OFF, interior lamps OFF, test for less than 1.0 ohm between the ground circuit terminal B and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A and ground.

⇒ | 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 REC.

4. If all circuits test normal, replace the inoperative vanity mirror.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Sunshade Replacement

• | Cargo Lamp Replacement

• | Dome Lamp Replacement

• | Headlamp Switch Replacement

• | Instrument Panel Storage Compartment Lamp Replacement

• | Overhead Console Reading Lamp and Bulb Replacement

• | Automatic Transmission Range Selector Lever Replacement

• | Control Module References for REC replacement, setup, and programming