Cadillac Repair: low voltage alternator, voltage output, batt

Question
I have a 87 caddy delagance. My alternator has a low voltage output. I have replaced battery and the alternator is new. I purchase that and batt new. The reason why I did that is because the batt keep dying. I mounted the alternator the car ran for about 2 days then the batt died. I then check batt which was fine and also the alternator which was fine. But the voltage is only 12 and chnage. I checked the wiring to the batt and the ground mount but I still can't get the voltage up and the regulator is in the alternator

Answer
Hello,

The alternator is not working, whether you changed it or not. If working correctly, you should see about 14.2 volts. The 12 volt reading you have is only residual battery power which will cause the engine to stall when it gets to 9-10 volts.

You could have a bad alternator even if replaced, bad wiring to and from the alternator. You could have a blown guage fuse as well.

When the alternator is working with engine running and lights on, the alternator will make a screaming sound.

Rob