High Beam Indicator Malfunction

HIGH BEAM INDICATOR MALFUNCTION




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
With the headlamp switch in the ON position, the headlamp switch headlamp ON signal circuit is grounded through the turn signal/multifunction switch at G200. In response to this input, the body control module (BCM) provides ground to either the headlamp low beam relay control circuit or the headlamp high beam relay control circuit. The position of the headlamp dimmer switch determines which relay coil has ground. The BCM supplies ground to the relay coil circuits, if the headlamps are necessary. The underhood fuse block supplies battery positive voltage to both relay switch circuits. When the headlamp high beam relay coil is energized, current flows through the LT HI BEAM and the RT HI BEAM fuses to the high beam headlamps. The high beam headlamps are grounded at G104. The headlights may be switched to high beam with the movement of the headlamp dimmer switch lever. With the headlamp dimmer switch in the high beam position the BCM sends a message via GMLAN to the instrument panel cluster (IPC) requesting the IPC to illuminate the high beam indicator.

CIRCUIT/SYSTEM TESTING

High Beam Indicator Inoperative
1. Ignition ON, install a scan tool and command the high beam indicator ON.
- If the high beam indicator illuminates, replace the BCM.
- If the high beam indicator does not illuminate, replace the IPC.

High Beam Indicator Always On
1. Ignition OFF.
2. Replace the IPC.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Control Module References for BCM and IPC replacement, setup, and programming