There is no single control to deactivate the Ambient Light Sensor (ALS) system. The automatic adjustment of the display and keyboard are set independently.
Follow these steps to turn the automatic display brightness feature on or off:
- 1. From the Apple menu, choose System Preferences.
2. From the View menu, choose Displays.
3. Click the "Automatically adjust brightness as ambient light changes" checkbox.
Follow these steps to turn the automatic keyboard brightness feature on or off:
- 1. From the Apple menu, choose System Preferences.
2. From the View menu, choose Keyboard.
3. Click the "Illuminate keyboard in low light conditions" checkbox.
You can also turn on or off the keyboard illumination feature by pressing the F8 key. This selection appears in the Keyboard pane of System Preferences.
These keys only respond in this way when the ALS is turned on. If you press the keyboard illumination control keys (F8, F9 and F10) and you see a dimmed graphic with the prohibitory sign (see below), the sensed ambient light is not low enough for the keyboard illumination to work.
Note: Not all 15-inch models of PowerBook G4 include the backlit keyboard and ambient light sensor. To determine if your model includes these features see if the F8, F9, and F10 keys have the ambient light sensor icons printed on them.
If these icons are not printed on the keys, then these features are not present in your model.