Daytime Running Lamp: Description and Operation

For the visibility and safety of all drivers, the daytime running lights will turn on automatically when the engine is running and the parking brake is released. Under these conditions, the head lamps will illuminate with a minimal amount of load on the charging system. (It the parking brake is applied while the engine is running, the load lights will turn off.)
With the ignition switch in ON position, battery voltage is applied to the head lamp relay coils and the day time running lights (DRL) control module.
As the DRL control module detects the generator running and the parking brake switch off signals, 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.
The high beam head lamps illuminate to about 90% of their capacity with the DRL system activated.