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.

### DTC Descriptor

DTC B2585 00: Park Lamp Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Park Lamp Switch ON Signal | 1 | 1 | 1 | --
Park Lamp Relay Control | 1 | 1 | B2585 00 | --
License Lamp Control | 1 | 1 | 1 | --
Park Lamp Control | 1 | 1 | 1 | --
License Lamp Ground | -- | 1 | -- | --
Marker Lamp - LF Ground | -- | 1 | -- | --
Marker Lamp - RF Ground | -- | 1 | -- | --
Marker Lamp - LR Ground | -- | 1 | -- | --
Marker Lamp - RR Ground | -- | 1 | -- | --
Park Lamps - LF Ground | -- | 1 | -- | --
Park Lamps - RF Ground | -- | 1 | -- | --
Tail/Stop and Turn Signal Lamps - LR Ground | -- | 1 | -- | --
Tail/Stop and Turn Signal Lamps - RR Ground | -- | 1 | -- | --
Turn Signal/Multifunction Switch Ground | -- | 1 | -- | --
1. Park, License, and/or Tail Lamps Malfunction

### Circuit/System Description

Battery voltage is applied at all times to both the coil and switch sides of the PARK LAMP relay located in the underhood fuse block. The turn signal/multifunction switch is suppled with ground at G201 at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the park lamp relay control circuit. This energizes the park lamp relay coil causing the relay switch contacts to close allowing battery voltage to flow through the LT PRK LAMP and RT PRK LAMP fuses to all of the park, tail, license, and marker lamps.

### Conditions for Running the DTC

• | Battery voltage must be between 9-16 volts.

• | Park lamps ON.

### Conditions for Setting the DTC

DTC B2585 00 will set when the BCM detects a short to voltage in the park lamp relay control circuit.

### Actions Taken When the DTC Sets

When DTC B2585 00 is present, the park lamps will not operate.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

### 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 X2 harness connector at the underhood fuse block.
2. Connect a test lamp between the control circuit terminal 6 and B+.
3. Command the Parking Lamps 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 BCM.

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

4. If all circuits test normal, replace the underhood fuse block.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Underhood Electrical Center or Junction Block Replacement

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