Is it the Alt. or Volt. Reg. ?

Electrical and Ignition

  1. 64conv65hard

    64conv65hard FABO Gold Member FABO Gold Member

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    Need some help on charging issues. Coming home last night from the White House after HBO filming with the 65 Valiant I noticed the Amp meter on discharge. Put my meter on the battery when I got home and sure enough, not charging. I've upgraded to the elect. volt. reg. a few years ago and new alternator at that same time. What are the test procedures to determine whether it's a bad voltage regulator or a bad alternator? Thanks.
     
  2. kt340sport

    kt340sport Well-Known Member

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    Usually if the regulator is bad , needle will not fluxuate back and forth, stays it the middle , prob brushs are bad in alternator , you can change them on the car i would take one out have a look all you need is 1/4 socket and nut driver , you could buy them in apackage of two , when i was doing auto parts.
     
  3. TrailBeast

    TrailBeast Slightly Twisted Member

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    If your alt is a dual field (Three wires connected to it) ground one of the field wires to the alt case and if the alt is ok it will go to full charging output.
    The easy way to tell is that it will pull the engine idle down, and the whine from the alt will get louder.
    Don't rev it while doing that though, cause you could blow something from overvoltage.

    Just ground a field terminal to the alt case and see if the idle drops.

    If it does then it's the regulator.
    If not, then it's the alt.
     
  4. 67Dart273

    67Dart273 Well-Known Member

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    • TrailBeast

      TrailBeast Slightly Twisted Member

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      I forgot to add that you diconnect the terminal from the field that you ground to the alt first, (Sorry)

      My point was to tell someone how to find out in less than 5 seconds, not to train the OP in automotive electrics.

      But hey, maybe the OP want's to spend all day figuring it out.:read2:
      I rather like getting to the point and fixing it.
       
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      • 64conv65hard

        64conv65hard FABO Gold Member FABO Gold Member

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        67Dart273 and TralBeast,
        Thank you both for the info. I will post later to what I found. Again, Thanks.
         
      • txstang84

        txstang84 Well-Known Member

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        ...just looked up ones for my '72...$5 for a set of brushes...

        I wish I could say I remember the needle doing funky stuff when my regulator went to full ground and my charge spiked to 18V, but I'd already bypassed the ammeter by that time.
         
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