Where is the ambient light sensor on a MacBook Pro?
The ambient light sensor on the newer Unibody MacBook Pro (all models: 13″, 15″, 17″) is located directly next to the iSight camera at the top of the display. You can verify the location by holding your hand over the area to the left of the iSight camera and watch as your screen dims and the keyboard lights brighten.
The location of the ambient light sensor on the pre-unibody older MacBook Pro’s (all models: 15″ and 17″) is located inside the grills of the speakers near the keyboard. Again you can verify this by holding your hands over the speaker grills and watch as the screen backlighting adjusts based on the change in the ambient lighting.
If you’d like, you can stop the MacBook Pro screen from dimming by adjusting various System Preferences.