please help my alternator is only running at 12 volts, i changed the battery and terminal leads, i hope it is not the alternator. Does anyone have any other ideas what it could be, thanks.

 

It sounds like an alternator problem It should be running about 13.8 - 14.5V. As long as all connections are tight on the battery and alternator and the fuses are good, I would plan on buying one.

 

I agree, usually when it reads low like that its bad, almost positive since you already replaced the battery.
TEST
While the car is running diccontect the negative battery cable if the car stops running it is most likely the alternater.

This means the car is relying on the battery alone to produce current for spark and by removing the battery cable you tested to see if the alternater was producing enough power to keep the car running. If this is true your driving time is limited to how much juice the battery has left and that wont last long.

Some auto parts store will test for free a load tester for the battery they can do this while its in the car or out.
they can test the alternater also on a bench tester, pretty sure you have to pull it out first.

 

NO, NO, NO, Never test an alternator like this! This method is okay on an older carburated vehicle with no accessories on. It can blow the PCM to say the least as well as other electronic equipment on a fuel injected car and will full field the alternator and cause a voltage spike. You can do what you want on your own car at your own risk.