Hi My 06 1.6 Zetec has started showing the battery waring light every now and again, it tends to be on more than it is off but can seem to stay off for quite a while somtimes. When it does come on the heated front winscreen button will not light up, so i assume its not working and when the lamp is off it works. I have checked the battery voltage with the diagnostic test and looks ok, when engine is running reads 13.5 volts. Any thoughts ? Thanks Matt