Ok add me to having this problem. Two days ago it was working fine as well as the auto brightness on the screen. Yesterday, brought it to apple to have the logic board changed (known nvidia video card issue). Picked it up today, in the store I noticed the case was not put back together correctly, as well as bent, I had them fix that and did not think of anything else. I get home and i am in a dark room and the screen is a bright as can be, and the backlit keyboard is off. I dim the screen and try the backlit keys no good i turn a light on and screen stays dim. I believe there is a defect in the sensors and it seems I am not the only one with this problem.
Has anyone found a fix to this I am not really happy with the apple store right now and the store is not close to my house but do have to go at least once more.
I have had a total of 7 in there the first three were fine, the third one was missing screws and case was not snapped close, the fourth did not power up the first time and casing was bent above the cd drive, this is the fifth one which also is having cd/dvd reading issues now, and there is one more there which I will be very carefully looking over as long as I can in the store.