Alternator warning lamp?

[h0mbre]

Hey guys

Just registered today, what a wealth of information this site is!!, much better than the forums for my Mazda :P

Unfortunately I got side tracked and ended up reading other articles while looking to find some info on the battery lamp which I've learnt is the alternator warning lamp, search brought up nothing so I thought I'd make a thread.

Old man has a 2000 AU Falcon Forte, called me up today saying the car won't start and he's stuck, I left uni and drove to where he was and straight away knew the battery was flat so I gave it a jump start and it started fine but I could tell power was low (dash lights were barely on).

Battery was old so we bought a new one but I'm pretty sure the battery isn't the problem here.

The Alternator Lamp is still lit, does this mean the alternator is borked?

What else can cause the lamp to come on?

Cheers guys, thanks in advance

Mun