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 | 5 | B2555 05 | B2555 05 | --
Inside Rearview Mirror Lamps Control | B1480 00 | 5 | -- | --
Left Front Door Ajar Switch Signal | 4 | 4 | 4 | --
Right Front Door Ajar Switch Signal | 4 | 4 | 4 | --
Rear Compartment Lamp Control | 1 | 1 | 1 | --
Rear Compartment Lid Release Switch Signal | 3 | 3 | -- | --
Rear Compartment Lid Ajar Switch Signal | 2 | 2 | 2 | --
Trunk Release Relay Control | B3265 06 | B3265 06 | B3265 01 | --
Door Lock Actuator - Driver Ground | -- | 4 | -- | --
Door Lock Actuator - Passenger Ground | -- | 4 | -- | --
Inside Rearview Mirror Ground | -- | 5 | -- | --
Rear Compartment Lid Ajar Switch Ground | -- | 2, 3 | -- | --
Rear Compartment Lamp Ground | -- | 1 | -- | --
Rear Compartment Lid Release Switch Ground | -- | 3 | -- | --

1. Rear Compartment Courtesy Lamp Malfunction
2. Rear Compartment Lid Ajar Switch Malfunction
3. Trunk Release Inoperative
4. Door Ajar Switch Malfunction
5. Inside Rearview Mirror Courtesy Lamp Malfunction

### Circuit/System Description

The INT LIGHT fuse supplies battery voltage to the inadvertent load control relay located in the body control module (BCM). The inadvertent load control relay is a non removable relay. The BCM applies ground to the inadvertent relay control circuit which energizes the inadvertent load control relay coil. With the relay coil energized, the switch contacts close allowing battery voltage to flow from the INT LIGHT fuse to the inside rearview mirror lamps through the inside rearview mirror lamps supply voltage circuit. The inside rearview mirror lamps are controlled by a 3 position (OFF, DOOR, ON) switch. When the inside rearview mirror switch is placed in the DOOR position, the lamps are controlled by the BCM by grounding the courtesy lamp control circuit. When any door is opened, the jam switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input, the BCM will activate the inadvertent relay control circuit, providing battery voltage to the inside rearview mirror lamps. The BCM also provides ground to the inside rearview mirror lamps through the courtesy lamp control circuit. When the BCM receives a rear hatch open input, the BCM will activate the rear compartment lamp control circuit to provide battery voltage to the rear compartment lamp. The rear compartment lamp is provided ground permanently at G402.

### Reference Information

#### Schematic Reference

• | Interior Lights Schematics

• | Release Systems 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. Observe the scan tool driver door ajar switch parameter located in Keyless Data while opening and closing the driver door. The reading should toggle between DOOR AJAR and DOOR CLOSED.

⇒ | If the reading does not change between the commanded states, refer to Door Ajar Switch Malfunction.

2. Observe the scan tool door ajar switch parameter located in Keyless Data while opening and closing the passenger door. The reading should toggle between DOOR AJAR and DOOR CLOSED.

⇒ | If the reading does not change between the commanded states, refer to Door Ajar Switch Malfunction.

3. Observe the scan tool trunk ajar switch parameter located in Keyless Data while opening and closing the rear compartment lid. The reading should toggle between TRUNK AJAR and TRUNK CLOSED.

⇒ | If the reading does not change between the commanded states, refer to Rear Compartment Lid Ajar Switch Malfunction.

### Circuit/System Testing

#### Door Ajar Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative door lock actuator.
2. Ignition OFF, interior lamps OFF, doors CLOSED, test for less than 5.0 ohms between the appropriate ground circuit terminal listed below and ground.

• | Door lock actuator - driver ground terminal 6

• | Door lock actuator - passenger ground terminal 3

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

3. Ignition ON, verify the scan tool door ajar switch parameter is DOOR CLOSED.

⇒ | If the scan tool displays DOOR AJAR, test the appropriate signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the BCM.

• | Left front door ajar switch signal terminal 4

• | Right front door ajar switch signal terminal 1

4. Install a 3A fused jumper wire between the appropriate signal circuit terminal listed below and ground. Verify the scan tool door ajar switch parameter is DOOR AJAR.

• | Left front door ajar switch signal terminal 4

• | Right front door ajar switch signal terminal 1

⇒ | If the scan tool displays DOOR CLOSED, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, test or replace the inoperative door lock actuator.

#### Inside Rearview Mirror Courtesy Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
2. Ignition OFF, scan tool OFF, interior lamps OFF, test for less than 1.0 ohm between the appropriate ground circuit terminal listed below and ground.

• | Inside rearview mirror ground terminal 6

• | Inside rearview mirror ground terminal 8 (UE1)

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

3. Ignition OFF, scan tool OFF, interior lamps OFF, test for less than 1.0 ohm between the appropriate control circuit terminal listed below and ground.

• | Courtesy lamp control terminal 6

• | Courtesy lamp control terminal 1 (UE1)

⇒ | 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 BCM.

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

• | Inside rearview mirror lamps control terminal 7

• | Inside rearview mirror lamps control terminal 6 (UE1)

⇒ | 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.

5. If all circuits test normal, replace the inside rearview mirror.

#### Rear Compartment Lid Ajar Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the rear compartment lid ajar switch.
2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms 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 the scan tool trunk ajar switch parameter is TRUNK CLOSED.

⇒ | If the scan tool displays TRUNK AJAR, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3A fused jumper wire between the signal circuit terminal A and ground. Verify the scan tool trunk ajar switch parameter is TRUNK AJAR.

⇒ | If the scan tool displays TRUNK CLOSED, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, test or replace the rear compartment lid ajar switch.

#### Rear Compartment Courtesy Lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the rear compartment lamp.
2. Open the rear compartment lid.
3. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal A and ground.

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

4. Ignition ON, verify that a test lamp illuminates between the control circuit terminal B 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 BCM.

5. If all circuits test normal, replace the rear compartment lamp.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Rear Compartment Lid Switch Replacement

• | Rear Compartment Courtesy Lamp Replacement

• | Inside Rearview Mirror Replacement

• | Front Side Door Lock Replacement

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