Which is why I first asked you an important question, which you still have not answered!

Suspicion is always placed on the alternator when it's not that to be at fault.

So does your warning light work?

No your light won't illuminate if you are grounding it on the wire with the ignition on, it will though if you ground it, whilst connected to the wire.

It will charge irrespective, if revved hard enough.

Martin