For 1990-2009 cars

## Backup Lamps Malfunction Manual Transmission

### 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
--- | --- | --- | --- | ---
Backup Lamp Switch B+ | 1 | 1 | 1 | --
Backup Lamps Control | 1 | 1 | 1 | --
Backup Lamp - Left Ground | -- | 1 | -- | --
Backup Lamp - Right Ground | -- | 1 | -- | --
1. Backup Lamps Malfunction

### Circuit/System Description

Battery voltage is applied from the HTD/SEAT/BCK/UP fuse located in the underhood fuse block to the backup lamp switch when the ignition switch is in the RUN or CRANK positions. When the transmission is placed in the REVERSE position, the backup lamp switch contacts close providing battery voltage to the backup lamps. The backup lamps are permanently grounded at G401 for the left and G402 for the right. With both power and ground the backup lamps illuminate. Once the driver moves the gear selector out of the REVERSE position, the backup lamp switch contacts open and the backup lamps turn OFF.

### Reference Information

#### Schematic Reference

Exterior Lights Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Exterior 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

1. Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5 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. Connect the harness connector at the inoperative backup lamp.
4. Ignition OFF, disconnect the harness connector at the backup lamp switch.
5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

6. Verify that a test lamp does not illuminate between the control circuit terminal B and ground.

⇒ | If the test lamp illuminates, test the control circuit for a short to voltage.

7. Connect a 10 A fused jumper between the B+ circuit terminal A and the control circuit terminal B. Ignition ON, verify the backup lamps are illuminated.

⇒ | If the backup lamps do not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the inoperative backup lamp.

8. If all circuits test normal, replace the backup lamp switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Backup Lamp Replacement

• | Backup Lamp Switch Replacement

## Backup Lamps Malfunction Automatic Transmission

### 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
--- | --- | --- | --- | ---
Park/Neutral Position (PNP) Switch B+ | 1 | 1 | 1 | --
Backup Lamps Control | 1 | 1 | 1 | --
Backup Lamp - Left Ground | -- | 1 | -- | --
Backup Lamp - Right Ground | -- | 1 | -- | --
1. Backup Lamps Malfunction

### Circuit/System Description

Battery voltage is applied from the HTD/SEAT/BCK/UP fuse located in the underhood fuse block to the park/neutral position (PNP) switch when the ignition switch is in the RUN or CRANK positions. When the transmission is placed in the REVERSE position, the park/neutral position (PNP) switch contacts close providing battery voltage to the backup lamps. The backup lamps are permanently grounded at G401 for the left and G402 for the right. With both power and ground the backup lamps illuminate. Once the driver moves the gear selector out of the REVERSE position, the park/neutral position (PNP) switch contacts open and the backup lamps turn OFF.

### Reference Information

#### Schematic Reference

Exterior Lights Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Exterior 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

1. Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5 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. Connect the harness connector at the inoperative backup lamp.
4. Ignition OFF, disconnect the harness connector at the park/neutral position (PNP) switch.
5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

6. Verify that a test lamp does not illuminate between the control circuit terminal 4 and ground.

⇒ | If the test lamp illuminates, test the control circuit for a short to voltage.

7. Connect a 10 A fused jumper between the B+ circuit terminal 5 and the control circuit terminal 4. Ignition ON, verify the backup lamps are illuminated.

⇒ | If the backup lamps do not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the inoperative backup lamp.

8. If all circuits test normal, replace the park/neutral position (PNP) switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Park/Neutral Position Switch Replacement

• | Backup Lamp Replacement