Daytime Running Lamp: Description and Operation

Voltage is always applied to all of the headlamp and park lamp relays. These relays are located in the relay box. The Body Control Module (BCM) activates the DRL (high beam head lamps at half intensity) by grounding the DRL relay and the LH and RH high beams relays whenever the ignition switch is in the ON position, the low beam headlamps are OFF, and the transmission is not in the PARK position. When the headlamp switch is in the HEAD or PARK position, the DRL is disabled and the low beam headlamps are ON. The DRL can also be overridden by the Twilight Sentinel (TS) and the wiper ON operation.