Daytime Running Lamps (DRL)

When the ignition switch is in the RUN position, the ambient light sensor indicates daylight, and the gear selector is not in the PARK position, the Daytime Running Lamps (DRL) are activated. When these conditions have been met, the Lamp Control Module (LCM) supplies battery positive voltage (B+) through CKT 593 (DK BLU) to the high beam headlamps in series. Because the high beam headlamps are in series, they split the voltage supplied by the LCM and the high beam headlamps light at a reduced intensity. The DRL are disabled if the gear selector is placed in the PARK position. When the ambient light sensor indicates darkness, the low beams are automatically turn on at regular intensity and the high beam go out.