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 CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Headlamp High Beam Relay Control | 2 | 1 | B2580 00 | -- |
| ||||
Circuit/System Description
Voltage is applied at all times to the headlamp high beam relay from battery voltage. When the multifunction switch is placed in either the 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 assemblies energizing the high beam solenoids.
Conditions for Running the DTC
The ignition is ON. The high beam headlamps must be commanded ON by the multifunction switch.
Conditions for Setting the DTC
The BCM detects a short to voltage on the headlamp high beam relay control circuit while trying to apply a ground to energize the relay.
Action Taken When the DTC Sets
The BCM turns off 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
Lighting Systems Connector End Views
Connector End View Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, turn headlamps ON and place the turn signal/multifunction switch in the headlamp high beam position. Observe the scan tool High Beam Relay Command parameter. The reading should display On and the high beam headlamps should illuminate.
Circuit/System Testing
Caution: The high intensity discharge system produces high voltage and current.
To reduce the risk of severe shocks and burns:
• Never open the high intensity discharge system ballast or the
arc tube assembly starter. • Never probe between the high intensity discharge system ballast
output connector and the arc tube assembly.
- Ignition OFF, disconnect the (C2) harness connector at the underhood fuse block.
- Connect a test lamp between the control circuit terminal 19 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 underhood fuse block.
| ⇒ | 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 |
