Reset Default Screen Brightness

Discussion in 'MacBook Pro' started by w00t951, May 11, 2010.

  1. w00t951 macrumors 68000


    Jan 6, 2009
    Pittsburgh, PA
    I have a 2008 Unibody Macbook Pro running Snow Leopard 10.6.3. I want to reset the default ambient brightness, because it stopped changing by itself after I manually changed the brightness with the keyboard. I made sure that ambient light changing was enabled in the System Preferences. From past experience, I think that deleting the preferences.plist file will do the trick, but I'm not sure. Any suggestions?
  2. MeAngry macrumors member

    Aug 24, 2009
    The Netherlands
    You can't disable the auto-brightness by changing brightness manually. You'd have to uncheck the box in sysprefs explicitly. So if that's on, it should work.

    If it still doesn't, your ambient light sensor might be defective. Is your keyboard backlight still turning on and off automatically? Cause if it does, there might be some other problem.

    You can doublecheck if it's working by keeping your hand in front of the webcam, the light sensor is right next to it.
  3. Pax macrumors 6502a

    Dec 12, 2003
    I had this problem when I used an add-in called FunctionFlip which changed the way the brightness function keys behaved

    Sometimes it was possible to kill the auto-dim aka ambient light sensor. It seemed to happen if I held eg F2 down to scroll up several levels of brightness in one go. I think if the auto-dim process receives several keypresses close together it can get stuck & not work

    Logging out and back in again solved the problem for me. But eventually I gave up using FunctionFlip.

    Try logging out and in again. If that fails try a reboot. If that fails try resetting the SMC. Maybe it's just a one-off glitch to do with the way you pressed brightness keys.

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