Self-timer lamp on my Nikon D300 won't turn off?

I used it for some self-timer shots, but when I turned it to a different shooting mode than self-timer, the self-timer lamp was still working prior to taking regular self-shot shots. I need to turn it off because it's wasting my battery and I don't need to use it. Looked it up in my manual and couldn't find anything on it.

That lamp has at least three functions: AF assist, red eye reduction and self-timer lamp. Check that the other two functions are turned off. Either one could be turning the lamp on before taking a shot.