2001 Ford Expedition Eddie Bauer 8 Cyl 5.4L
Warning lights go off and on. Battery drains within an hour
Battery drains within an hour even though alternator and battery are fine.
You have to have the alternator tested. If you want to do it yourself (shortcut method), charge the battery with a battery charger until the vehicle starts up on it's own without a jump. Then put a digital voltmeter across the positive and negative terminals and read the voltage. If the alternator is charging you should have a reading of about 14.2 volts +- .5 volts. If you are reading 12 volts +- .5 volts then it is likely that the alternator is no good. That is what it looks like from here.