For 1990-2009 cars

### Circuit Description

The body control module (BCM) monitors circuit 1138 from the solar light sensor to determine if the automatic headlamp system requires activation. If signal circuit 1138 is below 0.1 volts, the BCM will fail this DTC as current. The default for this failure is the automatic headlamp system will turn ON the exterior lighting system including the headlamps and park lamps.

### Conditions for Setting the DTC

• | The sensor input is less than 0.1 volts.

• | Short to ground or an open

• | The ignition is in RUN position.

• | The condition is present for 5 seconds.

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

• | The default to exterior lights on.

### Diagnostic Aids

• | Inspect for poor connection at the BCM. Inspect the 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 wiring harness for damage. Inspect for broken or chaffed insulation.

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

• | Auto headlamps will default to ON if sensor or system failure.

• | Dark condition exist if sensor input is above 4.1 volts for 15 seconds.

• | Daylight condition exist if sensor input below 3.5 volts for 30 seconds.

• | Input to the BCM