1995 Pontiac Firebird Owner's Manual - Page 125
1995 Pontiac Firebird Manual
Page 125 highlights
Voltmeter If you idle your engine for a while, the voltmeter reading might move into the yellow zone. reading If the stays in the yellow zone while you are driving, may you have a problem with the electrical charging system. Have it checked. While the voltmeter reads in the yellow zone, your battery not be able power certain may to electrical accessories, like ABS. (If this happens,your ABS INOP light will come on. See "Anti-Lock Brake System Warning Light" in this part.) If you must drive short distance with the voltmeter a turn off all your accessories, reading in a warning zone, including your comfort control and audio systems. You can read battery voltage your voltmeter.If it on reads less than 11 volts or more than 16 volts while your engine is running, andit stays there, you may have a problem with the electrical charging system. Have it checked right away. Driving with the voltmeter reading in a warning zone could drain your battery. 2-78