[Main 9000 Bulletin Board | BBFAQ | Prev by Date | Next by Date | Post Followup ] Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos Assuming you haven't fixed it already... Like This Post: - Subscribe to Daily Digest for this Bulletin Board Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Sun, 9 Mar 2003 20:57:07 In Reply to: 90 9Ks- voltage drop from 13+ to nothing, Ryan [Profile/Gallery] , Fri, 7 Mar 2003 19:02:46 Alert me when someone posts in this thread: Members do not see ads below this line. - Help Keep This Site Online - Signup

YOu never mentioned the Battery light - did it come on at any point in time?

For simplicity, there is the Voltage regulator and brushes, and they're bolted into the back of the alternator. All the brushes do is give the electrical current a way to get from the moving part of the alternator to the part that isn't rotating. The job of the Voltage Regualtor is to, well, regulate the voltage. As an alternator spins faster, it outputs more voltage. Since car engines run at different speeds, this could make things interesting. The VR controls electromagnets inside the alternator so that the output voltage is pretty stable at all engine speeds.

There isn't a whole lot to go wrong inside an alternator - it's just wire and some bearings. If it doesn't make a sound like a spoon caught in a garbage disposal, the bearings are fine. The wire usually doesn't die. As the others have said, there are diodes, which are electrical one-way valves. If one of them dies, you'll get no voltage out from the alternator.

My approach is to replace the VR first. I can do it with the alternator in the car, so it's quick. You can pick one up for $40-$50, sometimes less. If that doesn't fix it, then it's the alternator. I'll buy a quality rebuilt unit, and pull the new VR out of the old alternator before I send it back as a core. Now I've got a spare VR, which is a good thing.

A shop can test the diodes in the alternator.

So - did the BAttery light come on when the voltage dropped?

posted by 12.90.160...

• 90 9Ks- voltage drop from 13+ to nothing, Ryan , Fri, 7 Mar 2003 19:02:46
  • Assuming you haven't fixed it already..., Ari , Sun, 9 Mar 2003 20:57:07 <-- Viewing This Message
  • Alt. has bearings, brushes running on smooth(long), Lu, Fri, 7 Mar 2003 22:55:30
    • sweet merciful crap, lu, Ryan , Fri, 7 Mar 2003 23:23:22
      • Re: sweet merciful crap, lu, Lawrence, Sat, 8 Mar 2003 08:42:50
      • Thats what they are made of and how they work,, Lu, Sat, 8 Mar 2003 07:54:11
        • from the symptoms..., Ryan , Sat, 8 Mar 2003 11:32:41
          • Re: from the symptoms..., jim kane, Sat, 8 Mar 2003 14:07:33

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