05 500 3.0 SE replaced alternator 4 days ago drove for couple days then battery light came on replaced battery today light came back on? Its a reman alternator with warranty and brand new battery

 

Aftermarket alternators don't have the greatest reputation when it comes to Ford vehicles. If all the connections are clean and good (those coming from and going to the vehicle's PCM) , might consider getting an alternator from Ford.

 

Found the problem. when taking the alternator off had to take serpentine belt loose. Now need to tighten it back up. Ive been told several ways on how to do this. Can someone that has done this on a 05 500 explain to me how to do this so I don't screw anything up? TIA

 

I went thru a similar issue a couple years ago with my 2006 Ford by 500 limited. Battery went bad, and I hooked up a charger/booster. After replacing the battery, my battery light stayed on. I took it to a mechanic and he replaced the alternator. My battery light stayed on, he said I need a new pcm. Very expensive. So, I took the car to another mechanic and he told me the alternator was bad. I said I just had it replaced, he said, well all I know is it's bad. He replaced the alternator, and told me that he is had to be test three different alternators before getting a good one. I've heard some say to only use a genuine Ford alternator, so it is an issue. The other thing I learned, never hook up a battery booster to any new car or you can do some serious damage.