I have a 24" LED Cinema Display and can no longer control the brightness settings in OSX I believe when I applied the recent java/bluetooth updates the slider disappeared upon reboot. I did some searching and can't come up with a way to get it back. I'm using a 15" Unibody MBP, and the brightness slider for that screen is available and does work. I also tried setting the keyboard shortcuts on my main keyboard (external) to turn up/down the brightness but they won't function at all. I have tried zapping the PRAM, repairing permissions, and disconnecting/reconnecting the display, as well as booting with no external display and nothing has made the slider reappear. I also logged-in as a different user and the slider is not there for the Cinema on that profile either. I really, really hope I don't have to reinstall OSX to get rid of this but I'm out of ideas. I would love some help/ideas if you've got them. The worst of it is that I turned down the brightness to less than half (when it worked) becuase I had a headache and now it's stuck there! I'm really beginning to wish Apple would have included some manual buttons on the darn thing... Thanks.
Ok, maybe a silly question but did you click "detect displays" with your MBP connected to your ACD. Make sure your MBP is working. You also will want to make sure that the ACD is set as your primary display - when I did that the brightness on the Apple keyboard would control my ACD. Cheers.
Yeah it's the primary display. I don't have an apple keyboard but I set the shortcut keys in system preferences to turn the brightness up/down on the display and they don't work. I'm thoroughly stumped.