Why would it be at 12v? You need at least 14.4 to get past internal battery resistance to charge if. Your batteries would both be dead if your alt only put out 12 volts.i was just thinking my alt has a built in regulator do you think that it is only set to 12v? Which would not let it go past 12v????
testing your gauge? get a dmm. Pull the isolator out and see if it changes...ok i forgot 1 important step testing my gauge first. Can anyone explain to me how to test the gauge and see if am really getting 13v 0r 12v