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 above the 4.75 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 headlamp and park lamps.

### Conditions for Setting the DTC

• | The sensor input is greater than 4.75 volts.

• | The ignition is in RUN.

• | The condition is present for 5 seconds.

• | No telltale is illuminated.

• | The default to all exterior lights is ON.

### Diagnostic Aids

• | Inspect for a 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 the 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 the fault.

• | A dark condition exists if the sensor input is above 4.1 volts for 15 seconds.

• | Input to BCM