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: Headlamp High Beam Control CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Headlamp High Beam Relay Control | B2580 | B2580 | 1 | -- |
1. High Beams Inoperative | ||||
Circuit/System Description
B+ is applied at all times to the headlamp high beam relay. When the headlmap dimmer switch is placed in either the flash to pass (FTP) or HIGH position, ground is applied through the signal circuits to the body control module (BCM). The BCM then applies a ground to the headlamp high beam relay control circuit. This energizes the relay and applies voltage through the HI BEAM fuses to both left and right headlamp assembly.
Conditions for Running the DTC
The ignition is ON. The high beam headlamps are commanded ON.
Conditions for Setting the DTC
The BCM detects a short to ground or an open/high resistance on the headlamp high beam relay control circuit while trying to energize the relay.
Action Taken When the DTC Sets
The BCM disables the headlamp high beam relay control for the remainder of the ignition cycle.
Conditions for Clearing the DTC
| • | The conditions for setting the DTC are no longer present. |
| • | A history DTC clears after 100 malfunction-free ignition cycles. |
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for Scan Tool Information
Circuit/System Verification
Ignition ON, command the High Beams ON and OFF with a scan tool. The headlamp high beams should turn ON and OFF when changing between the commanded states.
Circuit/System Testing
- Ignition OFF, disconnect the HI BEAM relay.
- Connect a test lamp between the control circuit terminal E20 and B+.
- Ignition ON, command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the circuit tests normal, test or replace the HI BEAM relay.
| ⇒ | 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 an open/high resistance. If the circuit tests normal, replace the BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for BCM replacement, setup, and programming
