Class 2 Dimming
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
The class 2 lamps will be at full brightness when the ignition is on and the park lamps are OFF. When the park lamps are turned on, the BCM applies a signal to the class 2 circuit to the IPC and DIC. The class 2 display will then dim to the level set by the dimmer switch. The brightness of all the class 2 displays is determined by a variable voltage signal produced by the dimmer switch. With the park lamps activated, the IPC and DIC will dim for night time viewing.