The daytime running lamps (DRL) feature supplies light in a steady illuminating state to provide added vehicle visibility during daytime driving.
The daytime running lamps feature requests that the low beam headlights be ON at a reduced intensity whenever the headlights are not requested to be ON by any other features, the ignition is in RUN position and the transmission is not in PARK.
Refer to EXTERIOR LIGHTS for schematic and connector information.
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 (11572) is in the RUN position.
- The headlamp switch (11654) is in the OFF or PARK position.
- The autolamps 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 (10849) 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. For additional information, refer to EXTERIOR LIGHTING - THUNDERBIRD .