Having some electrical problems recently...
Last week, I was driving at night and my radio cut off, along with my headlights and dash lights which got very, very dim. I took it straight home and by the time I got there I had practically no lights at all. Shut it off, tried to crank it again and sure enough the battery was completely flat.
I checked the alternator and the exciter wire had come unplugged. Bingo! I plugged it back in and then put the battery on a trickle charger for a couple of days. Then when it was fully charged, I cranked it up and noticed the battery light in the dash was staying on. So I took it to Auto Zone and let them test the alt. They confirmed very quickly that it was dead. I was fully fine with this cause I think it was the original alternator to the Jetta so it was probably just time for it to go anyways. I got a rebuilt Duralast with a lifetime warranty.
Couldn't remove the weird clutched pulley off the original alternator, luckily Sal had a solid pulley for me so I put that on and then installed the new alternator. Again, let the battery get a good charge on the trickle charger and started it up. Battery light is still on.
I took it back to Auto Zone tonight and had them test the battery, it tested good. Tested the alternator next and he said the diodes were good but it had a bad voltage regulator. It's internal so it should have had a new regulator in the first place.
All I can do now is take it back out and let them bench test it to further diagnose. Does this seem likely that I got a bad rebuilt alternator? I would think they are all tested before they are sold but who knows. Could something else be going on that would cause this? Does a bad voltage regulator mean it won't charge the battery?
