HDLPS Suggested Indicator
WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
If the park lamps are turned ON manually and the ambient light sensor detects a low light condition then the body control module (BCM) will send a class 2 message to the instrument panel cluster (IPC) to illuminate the HDLP suggested indicator.