Casio wave septor solar watch model NY-G?

I have the above watch, unfortunately the backlight does not work, as the watch is solar powered does anyone no if it has a back up battery just for the back light, I have lost the instructions for it, but remember there was a function that enabled the light to come on when you turned your wrist, does anyone know how to turn this function off, (maybe this will save the power for the backlight?)