alternator draining battery - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• alternator draining battery by dillenger1 on 27 Jan, 2009 15:03
• My alternator drains when not running,but it still charges ok.does this happen when the brushes go bad?Will replacing them help?
• #1 by jtanguay on 27 Jan, 2009 17:10
• souds like a diode possibly?
• #2 by dillenger1 on 27 Jan, 2009 17:36
• Now the diode you speak of where is it located?
• #3 by jtanguay on 27 Jan, 2009 17:40
• Quote from: "dillenger1"

  Now the diode you speak of where is it located?

  
  
  no idea.  but if it was broken in the 'open' position then it would allow electrons to flow in both directions, draining the battery.  it might be in the voltage regulator itself?
  
  when you shut the car off, check the exciter wire for any voltage reading.  it shouldn't have any AFAIK.
• #4 by the caveman on 27 Jan, 2009 21:45
• Some bosch alternators have removable  brushes and regulator. I don't remember if the diodes are with it,but i don't think so.
• #5 by Smokey Eddy on 28 Jan, 2009 03:56
• you 100% sure its the alternator that is draining the batt?