Underhood Compartment Lamp
WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
When the underhood compartment is opened the underhood compartment lamp illuminates, if the courtesy lamps supply voltage circuit of the BCM is activated (BCM awake).
The underhood compartment lamp illuminates when the courtesy lamps supply circuit of the BCM supplies voltage to the underhood compartment lamp and the underhood compartment switch closes, providing a ground path.