94 Dodge Caravan not charging battery

I have a 1994 Dodge Grand Caravan, 3.8 V6, auto, just rolled over 200,000 miles. The battery started going dead so I had it checked and they said it needed replacing. I replaced the battery and two days later it was dead. The van will be running just fine, then the check engine light will come on and the voltage gauge will drop from about 14 all the way down. I replaced the alternator and the same thing is still happening. I recharged the battery and watched it happen again. The check engine light will come on and the voltage guage will start dropping. If I turn the van off and restart it the voltage gauge will go back up. The one other thing I have noticed lately is the button you push in to turn on the air conditioner will stay lit even when you turn the key off. You have to push the button again to get the light on the button to go off. Could this be a short that is draining the battery? I pulled the check engine code by using the key on and off method. The codes were:
12 Battery or computer recently disconnected
47 Battery voltage too low and alternator output too low
55 End of codes
Can anyone help with this problem? Thanks

How is the ground? curroded?

No, the ground looks ok, good and tight and clean? What do I need to check next? Thanks

Get an ammeter and check the voltage while the vehicle is running... it should show a charge somewhere between 13-14volts. Does the Battery idiot light come on? If your voltage is low and the idiot light doesn't come on, you may want to check the bulb as well.

You may have to start removing fuses under the dash and elsewhere one at a time with the ammeter attached in an effort to isolate a possible short circuit.

Get an ammeter and check the voltage while the vehicle is running... it should show a charge somewhere between 13-14volts. Does the Battery idiot light come on? If your voltage is low and the idiot light doesn't come on, you may want to check the bulb as well.

You may have to start removing fuses under the dash and elsewhere one at a time with the ammeter attached in an effort to isolate a possible short circuit.


Check for the above, also you may have corrosion that has worked it's way up the battery cables. This will cause high resistence and low charging voltage. Make sure all the cables are hooked up, looks like 3 ground cables?

http://img.villagephotos.com/p/2003-12/537508/94CaravanCharging1.jpg