Principles of Operation

The Daytime Running Lamps (DRL) feature will illuminate the low beam headlamps, pulse width modulated, at approximately an 85% duty cycle when the following conditions exist:
^ The ignition switch is in the RUN position.
^ The headlamp switch is in the OFF or PARK position.
^ The auto lamps feature has not illuminated the parking lamps and the headlamps.
^ The transmission is not in PARK.

The headlamps are controlled by the Front Electronic Module (FEM) and the instrument cluster in all phases of operation. The headlamp switch is hardwired to the instrument cluster, which sends a command through the Standard Corporate Protocol (SCP) network to the FEM. The FEM also determines transmission range status from the PCM and outputs the appropriate voltage to the headlamps.