GM-GMC: charging system light on 98 chevy z71, chevy z71, negative battery

Question
The charging System Indicator Light has come on after the voltmeter continuously reading under 12.5. Could it just need a new battery?

Answer
Jamie. it is possible that the battery cannot achive 12.5 and hold the charge. I would definately have the battery load tested, however the battery will not cause the light to turn on. usually the light means the the alternator is not producing proper voltage (14.6) or amperage (35to65).  If you check the output of the alt and its 14.1 to 14.7 at the battery posts this does not meat that the alt is good check your amps too with a probe on the red wire on the back of the alt. A constant bad battery can quickly ruin a good alt. QUICK TEST.... remove the negative battery conection while its running.  Check your guage and light.  If the light when out  and or your voltage when up....bad battery. If not ....bad alt.  Remenber to check fuses, some had a charge fuse.