Does anybody know...............

[WRMZ71]

Does anybody know exactly what is happening when the generator light in your dash panel comes on? I looked this up in the haynes manual and they don't say anything about it. I got these new cool blue lights for my 71 but they don't make a dang bit of difference cause my alternator won't charge 14-15 volts on a consistent basis. When its working right it'll chargeabout 14.6 volts but the other half of the time it only charges just about 12. It's not enough to kill my battery or keep from firing her up every morning but dangit its annoying that the dumb dash light won't go out. Can anybody help me please???? THANKS