Hello All. I went to crank my truck yesterday and my battery light came on and will not go off. My battery seems to be holding a charge from the altenator and the field fuse under the hood is not blown. Any ideas on what would cause this to come on and stay on like that. I have a 2002 with the 5.4.Thanks in advance for any help that you would be able to provide. It has me pretty stumped.

 

put a volt meter on the battery when its running, anything over 13.5 is good, anything less than 13 is bad, if it reads only the battery voltage then the alternator is not doing anything. Do not trust the stupid idiot lights. If you dont have a meter then buy one.

 

Most likely you alternator. As your alternator gets older the brushes wear down and the springs get weaker and cannot hold the brushes against the rotating group.

 

Thanks a lot for ya'lls help. It ended up being my altenator