It will go out when the volts drop enough. New battery takes a long time to drop. I thought something was wrong with mine when I first got it put in, called and the guy told me with new batteries it can take a while, as battery gets older it will go off sooner. If it bothers you just turn lights on with key on and engine stopped and it will go out pretty fast. When my battery was new it would stay on 8 hours or so, doesn't take that long now.