Daytime Running Lamp: Description and Operation
OPERATIONWith the Ignition Switch in "RUN". the Main Light Switch in "OFF" or "PARK" and the Park Brake released, the Daytime Running Lamps (DRL) Module illuminates the Lo Beam Headlamps at reduced power.
Power for the Lo Beam Headlamps is provided by the Horn/DRL Fuse. Current flows through the Horn/DRL Fuse, the DRL Resistor and the DRL Module to the Headlamps. The DRL Resistor reduces power to the Lo Beams.
When the Main Light Switch is switched to "HEAD", the DRL Module switches full power to the Lo Beam Headlamps through the Headlamps Fuse, the Main Light Switch, the Multifunction Switch and the 188 (W/BK) wire.
The DRL Module also controls the Brake Indicator. If the Park Brake Switch is closed, the DRL Module will turn off the Lo Beam Headlamps and ground the Brake Indicator.