For 1990-2009 cars

### Circuit Description

The body control module (BCM) activates the headlamp relay when the light sensor senses a dark condition. Battery voltage is supplied to the headlamp relay through the BACKUP/TURN fuse UHFB. The BCM provides ground to circuit 352 to activate the headlamp relay. If the headlamp relay control circuit is shorted to ground or open for five seconds. DTC B2577 will fail.

### Conditions for Setting the DTC

• | Headlamp relay is commanded OFF.

• | Short to ground or open

• | Ignition in RUN

• | The condition is present for 5 seconds.

• | No light will illuminate in the instrument panel (I/P).

### Diagnostic Aids

• | Inspect for poor connection at the BCM. Inspect harness connectors for backed-out terminals, improper terminal mating, broken connector locks, improperly formed or damaged terminals and poor terminal-to-wire connection -- terminal crimped over wire insulation and not conductors.

• | Inspect the wiring harness for damage. Check for broken or chaffed insulation.

• | If fault is suspected to be intermittent, wiggling the harness wiring may help in locating fault.