Daytime Running Lamp: Description and Operation

Daytime Running Lamps (DRL)
The daytime running lamps (DRL) system is designed to switch the low beam headlamps ON at a reduced intensity and the tail lamps (including license plate lamps) at normal intensity under the following conditions:

The ignition is in the RUN position.

The headlamp switch is in the OFF position.

The parking brake is in the OFF position.

The transmission is in gear (vehicles with automatic transmission).

If the above conditions are met, the low beam head lamps are illuminated by an 11.8 volt pulse width modulated signal (PWM).

The side lights are illuminated normally (from the GEM), the tail lamps and the license plate lamps are illuminated by the REM.

The daytime running lamps are extinguished under the following conditions:

The headlamp switch is set the PARK position (all vehicles except Canada).

The headlamp switch is set to the "headlamp" position.

The daytime running lamps interact with the following components:

The instrument cluster.

The generic electronic module (GEM).

The rear electronic module (REM).