Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ambient Light Sensor Signal | B2645 03 | B2645 07 | B2645 07 | -- |
Ambient Light Sensor Low Reference | -- | B2645 07 | -- | -- |
Left Front Turn Signal Lamp Supply Voltage | 1 | 1 | 2 | -- |
Right Front Turn Signal Lamp Supply Voltage | B2615 00 | 1 | 2 | -- |
Left Front Turn Signal Lamp Ground | -- | 1 | -- | -- |
Right Front Turn Signal Lamp Ground | -- | 1 | -- | -- |
| ||||
Circuit/System Description
The ambient light sensor is a light sensitive transistor that varies the voltage signal to the body control module (BCM) based on outside lighting conditions. When the ambient light sensor indicates daytime conditions with engine running, the body control module (BCM), will then apply battery voltage through the front turn signal lamp supply voltage circuits illuminating the left and right front turn lamps. Any function or condition that turns the headlamps ON will cancel DRL operation.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
| • | Ignition ON, verify that the left and right front turn signals operate. If not refer to LINK. |
| • | Ignition ON, observe the scan tool Ambient Light Status parameter while carefully supplying sufficient light to simulate daylight conditions to the ambient light sensor. The reading should be Day. |
| • | Engine running in daylight conditions with the headlamp switch in the Auto position, the front turn signal lamps should illuminate as daytime running lamps. |
Circuit/System Testing
- Carefully supplying sufficient light to simulate daylight conditions to the ambient light sensor.
- Ignition ON, observe the scan tool Ambient Light Status parameter. The reading should be Day.
| ⇒ | If not the specified value, replace the ambient light sensor. |
| ⇒ | If the specified value, replace the BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
