Whenever I leave my truck overnight the battery dies. I can disconnect it and hook it up the next day and the truck will fire up. I have tested the battery and it is good (it is fairly new). I am pretty sure that the alternator is charging it because the battery never dies if I keep diconnecting it when it isnt running. I assume there must be a short somewhere that is draining my battery when its parked. I have a decent meter, so can I hook it up somewhere to see if there is voltage getting drawn from the battery when it is off? My neighbor told me that the alternator may have a faulty resistor (???) that is draining the battery. Also, what should the meter read as output from the alternator when the engine is running? The battery reads 12.6VDC with the engine off and 13.4 running.