Hey everyone,
I have my 1999 F150 along with my 2003. My 1999's battery light came on while driving this morning. Battery test showed low but good. Alt test on vehicle showed 10.99 charging. I replaced the alt. Well, the light still stays on. The excide battery in less than 1 year old. I am trying to charge it right now. Can anything else cause this? This vehicle doesn't have any type of external regulator, does it? Could a blown fuse cause this? I am a novice so I really count on you guys to help.
Joe

 

10.99 is not charging. You need to replace your alternator.

 

Well, As usual ,I went too deep again. The 20 amp fuse for the alt was blown. I now have a new alt installed. With 140k miles, I would have needed one soon probably.
So, the answer, is check the fuses first. My tester doesn't say anything about fuses, just that it wasn't charging.
Will I ever learn??
Joe

 

As a general rule of thumb, Yankee is correct. A battery light when the engine is running usually points to the alternator. You discovered one of the exceptions.

As I remember a battery light when the engine is not running usually means it the battery.