Is my backlight sensor broken?

Hi,

I have a question about the backlight sensor. The previous generation macbook pro's, I remember, I could simply cover the speakers with my palms on both sides of the keyboard and the keyboard would easily light up. But now it no longer does? In fact, I've enabled the automatic keyboard illumination, but in fully bright rooms, it will still be faintly lit, and then if i go into pitch black rooms, the light level will remain the same, it never changes to adjust for the room?! what gives? is this normal? am I doing something wrong?

thanks for the help guys!