Daytime Running Lamp: Description and Operation

Circuit Description
For the visibility and safety of all drivers, the daytime running lights will turn on automatically when the park brake is switched off, and the engine is running. Under these conditions, the head lamps will illuminate with a minimal amount of load on the charging system. (If the parking brake is applied while the engine is running, the head lights will turn off.)

With the ignition switch in ON position, battery voltage is applied to the head lamp relay coils and daytime running lights (DRL) control module . As the DRL control module detects both the generator running and the parking brake switch OFF, ground is provided to the DRL relay. Battery voltage from DRL fuse is then provided to the high beam head lamps through DRL relay contact and DRL resistor. The high beam head lamps illuminate to about 90% of their capacity with the DRL system activated.