• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
High Beam Relay Control | 1 | 1 | B2580 00 | -- |
1. Headlamps Malfunction - High Beams |
The high beam headlamps can be controlled by two different inputs to the body control module (BCM), the dimmer switch and the flash to pass switch. When the BCM receives a high beam headlamps ON command, it grounds the headlamp high beam relay control circuit in order to energize the high beam PCB relay. With the relay energized, battery voltage is applied through switch side of the relay, both HI BEAM fuses, and the high beam supply voltage circuits to the high beam headlamps.
The high beam headlamps must be ON.
The BCM detects a short to voltage on the headlamp high beam relay control circuit.
The BCM will deactivate the headlamp high beam PCB relay for the remainder of the ignition cycle.
• | The condition responsible for setting the DTC no longer exists. |
• | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Headlights/Daytime Running Lights (DRL) Schematics
Exterior Lighting Systems Description and Operation
Control Module References for scan tool information
Ignition ON, command the High Beams ON with a scan tool. The High Beam Relay Command parameter should display On and the high beam headlamps should illuminate.
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the underhood fuse block. |
⇒ | If the high beam headlamps do not illuminate, test the control circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the underhood fuse block. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |