My backlight on my black jack 2 will not dim!?!?

My blackjack 2 will not dim when the backlight is set to go off. The whole screen turns white and is extremely bright. It runs down my battery in about 20 minutes. I have it set to dim after 10 seconds and after 10 seconds the screen goes completely white. Is there some setting I cannot find that will change it to dim completely rather than just go to a white screen or is my phone just messed up?