your alternator needs to be checked its free at most auto parts stores
Why would battery light come on then go off
If it is undercharging the battery yes, but if it is overcharging the battery no in most instances. If it fails completely the light will come on.
what causes the battery light to on a 2005 ford expedition to come on?
Battery
It could
Your battery is probably dying
when it doesnt come on when you put it in the phone or when its in 2 parts.........
Your battery is probably "broken" Check if you have disabled battery charging And if the charging light is on it is charging and its a good thing. Also check the adaptor with a multimeter (UNPLUG IT FIRST)
A bad stator causes the battery not to charge. That makes the battery light come on. Some other things that can cause the battery light to come on are corroded or frayed cables or connections or a loose/bad ground cable.
NO! where does the power (voltage and current) come from if the battery is flat/dead?
battery is on its way out or its not charging properly
probably have a bad alternator or voltage regulator or bad battery cables