Daytime Running Lamp: Description and Operation

DAYTIME RUNNING LAMPS (DRL)

The front turn signal lamps are used as both daytime running lamps (DRL) and turn signals lamps. The body control module (BCM) illuminates the front turn signals lamps in a non flashing mode for DRL operation. If the turn signal switch is activated during DRL operation, the appropriate turn signal will flash.

On vehicles with automatic headlamps, the DRL are designed to be automatically illuminated when the ignition is ON and the outside (ambient) light level is high as in daytime conditions (day mode). The DRL will not operate if the ambient light levels are too low (night mode). Light levels are detected by the ambient light sensor, a light sensitive transistor that varies its voltage signal to the BCM in response to changes to the ambient light level. When the BCM receives a day mode signal from the ambient light sensor it will then illuminate the DRL lamps. The automatic headlamps and park lamps will not operate when the DRL lamps are ON.

In the day mode, the ambient light sensor detects daylight and the BCM applies voltage to the LH and RH front turn signal lamps illuminating the lamps under the following conditions:
- The ignition switch is in the RUN position.
- The headlamps are OFF.
- The park brake is OFF (released).
- The transaxle is not in park.
- The RH or LH turn signal is OFF.

On vehicles with manual headlamps, the DRL are designed to be illuminated when the ignition is ON and the headlamps are OFF.

When the headlamps are OFF, the BCM applies voltage to the LH and RH front turn signal lamps illuminating the lamps under the following conditions:
- The ignition switch is in the RUN position.
- The headlamps are OFF.
- The park brake is OFF (released).
- The transaxle is not in park.
- The RH or LH turn signal is OFF.