The alternator may not be able to keep up to the voltage requirement of the vehicle check voltage output of alternator w/mechanical gauge
altenator
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
This light is used for 2 different purposes.(1) If the brake fluid is low,this light will come on.(2) light will come on when you engage the parking brake.
Your battery is probably dying
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
If your battery is not being charged , the battery light will come on in your dash