2000 ford windstar check charging system light stays on when I just replaced the alternator and the battery, and both have been checked again after installation

I would check age of battery. Batteries these days are made with cheaply coated parts and only last about 5 years. Many times a bad battery will over work the alternator making them go out. Since you have changed the alternator I am assuming that you checked and cleaned the battery connections.

You my need to have the alternator looked at again to see if it's charging you also have to look at the fuse for the alternator it may be blown. Also check the check the plug that goes to the back of the alternator make sure it is in all the way.

have the charging system checked out find out if its charging anything.this may have been why the battery light stays on.usually a bad battery won`t turn on the battery light as its used to let the driver know that the charging systems needs to be checked out.

I had this problem. i thought it was a parasitic drain but...
check your charging system. with the van running, check the voltage output accross the battery terminals. if its less than 14.1 check the inline fuse for the alternator (close to the alternator) if ok, replace the voltage regulator inside the alternator.

if the charging system is putting out 14+ volts then you need to start pulling fuses while van is off while monitoring the current draw between the positive battery post and the positive terminal clamp watching for a current drop. keep in mind the windstar will drain alot of current while off for the first 2 mins er so, then it will drop again in about 15 mins... time delay shutdown on several systems :)

Something is wired wrong draining electricity. Check the glove box light see if the radio works without the key. look for anything coming strait off of the battery not off of acc power.If it was a direct wire short out of nowhere the wire would have burnt up and been bare by now.Its somthing you have on or is staying on.

alternator.have charging system checked for free at autozone.

It could mean the alternator has gone bad already... with the car off, the battery leads should read 11-12V.. with the car on, the battery should read 13-14V.. if it's lower then it's not charging your battery and if it's higher, it's damaging your battery....

Check all connections to alt. and battery to make sure they are clean and tight, as it sounds like a loose or dirty connection someplace. Possibly something not tightened completely after battery and alt. replaced? (just enough to get the annoying light to go on occasionally)

I would check my wiring harness for faulty connections and possibly burnt wires. Also trace the wires from your alternator to the battery. check them over. The battery may need to be replaced. If you let it run down alot and kept jumping it.

Where did you buy alt,have had several issues with alternators from auto zone,But check belt tention and idle speed.