So I have a 2006 mustang GT the original alternator went out about 3 years ago. Probably had about 150,000 mi. Put in a TYC with a new battery and it died on the way home from work. Suspecting that this aftermarket alternator crapped out I got to rebuilt motorcraft and lo and behold it's not charging the battery either!? Some people have said replace the power wire from the alternator to the battery, other people said your battery has a short get a new battery and somebody else said check...

New alternator not charging battery.