Is battery or altenator faulty if battery light on and voltmeter at 1/4th dial? on 1997 GMC 3500 Pickup

warning light went on and meter indicated discharge when I started ignition.

Asked by for the 1997 GMC 3500 Pickup
I wouldn't pay too much attention to the voltmeter, but a battery light indicates a charging system failure.

Make sure the battery is fully charged and then test the charging system. Chances are the alternator has failed.