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 B2580 00: Headlamp High Beam Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Headlamp High Beam Relay Control | 2 | 1 | B2580 00 | --
1. Headlamps Inoperative - High Beams 2. Headlamps Always On - High Beams

### Circuit/System Description

When the body control module (BCM) receives a ground signal from the multifunction high beam or flash to pass (FTP) switch commanding to illuminate the high beam headlamps, the BCM will energize the high beam relay by grounding the high beam relay control circuit.

### Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

### Conditions for Setting the DTC

The high beam headlamp relay control circuit is shorted to voltage.

### Action Taken When the DTC Sets

The high beam headlamps will not operate or will remain always on.

### Conditions for Clearing the DTC

• | This DTC will clear on current status after the condition for setting the fault is corrected.

• | A history DTC will clear after 100 consecutive ignition cycles without a fault present.

### Reference Information

#### Schematic Reference

Headlights/Daytime Running Lights (DRL) 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 Verification

Ignition ON, command the High Beam ON with a scan tool. The High Beam Relay Command parameter should display On and the high beam headlamps should illuminate.

### Circuit/System Testing

1. Ignition OFF, disconnect the HI BEAM relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 86 and ground.

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

3. If all circuits test normal, replace the BCM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Relay Replacement

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