Hi I know this isnt the right place to post this but ive been a member so long I know this is the forum with all the Ford Brainiacs... Heres what i got folks.
Culprit..1999 ford windstar, 3.0
Problem.. battery light stays on constantly

Ok heres a little background for those want to try help me.
Im a wrenching on this van for an elderly lady on fixed income she came to me with head gaskets blown, Ive done all that work and she runs like a clock now, I discovered after resetting puter and running it the battery light comes on after about 45 seconds of running it.
I called her and she told me she bought 4 used batterys since october of 2010 and they all died.
so right away im thinking alternator (probably what your thinking too)
I know she doesnt have 210.00 my cost at Advance for this so i go to the junkyard and pull 2 that look like fine candidates one in particular had the hood closed and was a reman looked new. so for 16.00 a pop it was no brainer. I put in the reman with all the confidence and guess what the darn light popped back on. I tested the voltage running and shes putting out 14.44 volts on the money so i know its charging. I know her batterys good cause i swapped in 68 mustang battery that is brand new. and put hers in my mustang and it is charging fine. I just got back from a test run for the motor and ran every electrical component i could think aside from blowing the horn the whole way on 10 mile trip the lights stayed bright and the battery light stayed on.
could the pcm be reading faulty? there are no check engine lights on just the battery light any ideas would be a blessing. thanks folks and i do appoligize for running this on the f150 forum

 

Just some thoughts.

Did you check the voltage right at the battery? If there was a wiring issue, it might not be the same there.

Did she change batts because of the battery light, or did she actually have problems? It could be an issue with the circuit for the light. I forget the exact deal, but I have read about a condition that can cause the light to come on when there isn't a problem.

Not a lot of help, I'm afraid.

 

yes to checking voltage right at the battery, i had 14.23 at the battery during the check. as far as her other batteries went im assuming that the original alternator wasnt putting out the proper voltage it was putting out 12.28
yeah like you i think i too remember reading a forum somewhere about the pcm. thanks for your input it all counts!