Battery dies while driving, I pulled the alternator (which is a pain) and had it tested..its fine. battery still wont hold a charge..btw battery is fine. had it replaced too.

What's the voltage at the battery with the car running ? Testing an not guessing is the way to do proper diagnostic's ! Battery light staying on , is there B+ voltage at the alternator connection's ? A new alternator won't make a bit of difference if no power to the alternator . Looking at a wiring diagram an testing the electrical circuit ,doing voltage drop testing , plus checking for DTC'S - diagnostic trouble code's . Some vehicle's charging systems are computer controlled . And looking at a wiring diagram i see your vehicles charging system is computer controlled . If you have done so already , take it to the dealer

there is the starter current draw or battery not holding the current have the battery check like batt. load test
hope it helps

Battery light on ! alternator isn't charging . Test the alternator electrical circuits .Main cable on the back of the alt. should have B+ voltage .Pin # 3 at the connector on the alt. should have B + voltage - fuse F10 10amp under hood fuse box supply's B+ to pin #3 . Pin's 1 & 2 at the connector go to the PCM - engine computer . This is a computer controlled charging system .
Ford PCM controlled alternator testing

1. Check all the cable connections on the battery and on the alternator.

2. If they are all fine then have the alternator checked because from what you have described it is not charging. The usual problem is worn brushes in the alternator.

It's your alternator that may be the problem. Your thinking of the battery is wrong because everything on a running car is run off the alternator. Only if the alternator dies will the car continue to run off the battery-but not for long if any accessories are used. So the alternator runs everything AND recharges the battery until it is needed again to start the car.
Your alternator is barely keeping up with running the car, and is not apparently doing much to recharge the battery. Have the alternator tested.

I would not say for certain it is the alternator-there may be a problem in your a/c circuit. But first test the alternator...BTW, Kinsha, pulling off the neg. cable to check an alternator is as old school as me, but on modern electronics it is considered bad practice-electronics don't like little surges or peaks of power. Buy an inexpensive digital multimeter-it is fun learning as you go.

This is easy to test but you need a multimeter. Connect the multimeter to the battery and run the engine at a fast idle (say 2000 rpm). You should get a voltage reading anywhere from 14 to 15 volts if the battery is fully charged and the alternator is working. If the reading is around 12 volts, then the alternator is not working.

If alternator and battery is good, check the ground cables from the battery to the motor and frame grounds.

possibilities are connections at battery corroded or loose battery dieing not holding charge alternator not charging battery or starter shorted out or connection problem try to boost vehicle if starts have battery /alternator tested for proper working order

I would go to advance auto parts and have the battery tested, Also the alternator, The engine wont run if the alternator is bad, As soon as the battery goes dead the car will shut down, Any auto parts store usually will check the battery and alternator for free, make sure the battery is fully charged before you take it there. They will let you know what you need to replace...

if with the volt meter the amps go down while running and at increased rpms than your alternator is not charging right