Battery voltage is applied at all times to the left front cornering lamp PCB relay which is part of the underhood fuse block. When the turn signal switch is placed in the left turn position, ground is applied through the left turn signal switch signal circuit to the body control module (BCM) The BCM then applies a ground to the left cornering lamp relay control circuit energizing the relay. With the relay energized, battery voltage is applied through the switch side of the relay, the LF CRN LAMP Fuse, and the left front cornering lamp supply voltage circuit to the left front cornering lamp.

DTC B2590 00 will set when the BCM detects a short to voltage in the left cornering lamp relay control circuit.

When DTC B2590 00 is present, the left cornering lamps will not operate.

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

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
2. Connect a test lamp between B+ and the control circuit terminal K1.
3. Ignition ON, command the Left Cornering Lamp 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 an open/high resistance. If the circuit tests normal, replace the BCM.

4. If the circuit tests normal, replace the underhood fuse block.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.