Here’s an obscure piece of Mac voodoo that hopefully few people will ever need. I opened up my sleeping Macbook Pro this morning (the 15″ 2.2 GHz mid-2007 edition) and the keyboard backlighting was on full blast. Pressing the F8 key to turn it off did nothing. In fact, the backlight brightness display appeared with a little circle with a slash through it (what Apple calls the “prohibitory sign”).
So I tried using the keyboard preferences to turn off background illumination. No luck, still stuck. I tried rebooting but no luck, still stuck. I tried rebooting and zapping the PRAM. No luck, still stuck. I tried messing around on Google for a solution someone else used. No luck, still stuck (with apologies to my kids’ favorite book, One Duck Stuck by Phyllis Root).
So how did I finally turn off the stuck keyboard backlight on my Macbook Pro? I found a slightly hidden article on Apple’s support website describing how to mess with the Macbook Pro’s backlight ambient light sensor. Simply place a palm over the lefthand speaker grill, where the ambient light sensor lives, make your MBP think it’s in the dark, and, abracadabra, the keyboard backlighting turned off and the F8, F9 and F10 control keys were functioning once again.