Faulty Left Daytime Running Lamps
Left Daytime Running Lamps harness is open or shorted
Left Daytime Running Lamps circuit poor electrical connection
Faulty Body Control Module (BCM)
Engine Light ON (or Service Engine Soon Warning Light)
The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 V depending on outside lighting conditions. The Body Control Module (BCM) provides a 5 V reference signal to the ambient light sensor and the Heating, Ventilation, and Air Conditioning (HVAC) Module provides a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lamps or automatic lamp control when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the designated daytime running lamps ON. During low light conditions the BCM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel daytime running lamps operation.