Pontiac Battery warning light

I have just purchased a 94 Pontiac Grand Prix SE, today I noticed after a long drive that the battery warning light started to flicker on & off when idling and turns off when you put your foot on the accelerator pedal.
I was told that the car has recently had a new alternator - any ideas as to what the problem may be & what to check?

new alternator doesn't really mean it's new. get it checked and your battery may be done it's duty. is every thing stock like stereo.

sounds like the internal regulator is faulty.

also make sure you disconnect the battery when you replace the alt. if you do replace it.