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 |
| • | 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. |
