Charging system on my 1997 expedition

Volts slowly drop to where what quits ,The vehicle stops running ? Is the charge indicator light lit on the instrument cluster /? are any lights lit on the instrument cluster ? The instrument panel cluster (IPC) illuminates the charge indicator and the BATTERY NOT CHARGING message is displayed in the message center when the following occurs:
The engine control module (ECM)/powertrain control module (PCM) detects that the generator output is less than 11 volts or greater than 16 volts. The IPC receives a serial data message from the ECM/PCM requesting illumination.

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The IPC determines that the system voltage is less than 11 volts or greater than 16 volts. The IPC receives a serial data message from the body control module (BCM) indicating the system voltage.

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The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.

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The ignition is on, with the engine off

Lisa I'M sorry to say their isn't any fuse or fuses that can correct problems with our alterator.Their is what is called a fuseable line witch is basicaly reistance wire that will burn out if over loaded .However you would have nothing even with a new battery NO CRANKING.
The ALT .uses diodes it is AC alternating currant unlike DC direct current..The diodes olny allow the currant to flow in 1 derection and uses a voltage regulator to allow the systems that are DC the battery to charge and at the same time other systems that run on AC voltage to work as well .
Your best bet is to talk it to somebody who you trust and test what you get at the battery with the vehicle running if it reads 14 volts at the top of the battery DC then the ALT IS GOOD , Check the BAT , at this point with the NEGITIVE cable off the BAT. It should read at least 12 volts DC on a 20 volt Dc scale.
But likely it is the alternator

Did you try another guage? Just to be sure i would.

Sounds like it needs an alternator. If the alt. is working correctly it should charge at 13 - 15 volts. Your car is a 12 volt system. anything less than that is not charging, it's draining the new battery.

If you have a Battery charger, disconnect the Neg cable of the battery from the SUV and charge the battery overnight. When you get the SUV running, take it to Autozone or Oreillys for a free scan. Also ask them to do a Starter draw test and to analyze your charging system and Battery.

The Ford antitheft systems are really sensitive to low power. While your vehicle has a 12 Volt system, a fully charged battery will have 13.2 to 13.4 Volts in it. A drop of 10% in battery performance will drop the charge to 12 Volts or less. This is enough to make the anti-theft lock out the Starter.

I have seen Charging systems automatically turn off once a jumper cable is removed. You can see it on the dash gauges where the Alternator is working and remove the jumper and after several minutes a perfectly good Alternator stops working while you are driving. Then install a battery with a 13.2 Volt charge and everything starts working perfectly from then on.

I mention this because you may have felt the Battery was charging after the jump and really it was not. You have to watch the Volt meter in your dash while you drive, there will be no warning lights.

I hope I have been helpful with my solution and that you will get a scan on your SUV.

You have a faulty Voltage Regulator or relay in the power Distribution box under the hood.

did this problem start after the new alternator or is this the reason you replaced the alternator? sounds like a loose wire on the alternator or the battery post. make sure the battery terminals are clean from corrosion. if there is a hot spot on the wires or connectors that is a good sign that is a loose connection.

Yes,it is,the alternator is charging to much,this can lead to other component failures.Have the alternator changed,not just the regulator in the alternator,if a diode has burned threw,it can,and most likely is,putting out some ac voltage,witch is very bad for the ignition system,and it will put ac voltage in the battery.The pulsing is from ac voltage,not just a dc overcharge.The alternator should be 13.65 volts,to 14.25 volts,at the battery.Most of the time,when there is a pulse,in the lighting,and the alternator is charging around 15 volts,there is ac volts present.so this means,the battery would need to be changed also,to prevent any other problems.I hope this was helpful,and if so,please let us know,thank you.

The battery is most likely dead, and the alternator is shot. Take out the battery have it charged and load tested. Reinstall it start the car and use a volt meter to take a reading at the terminals. If your alternator is working it read about 14 volts DC. If it dosen't you need a new alternator.

check battery and cables.if battery is 12.5 volts. look at cables for looseness and corrosion.if corroded clean cables and battery post. also check to make sure the alternator is charging.