[Vwdiesel] bad alternator?

[LBaird119 at aol.com]

It's possible, that removing the red wires or battery terminal,  while 
running, can wreck the alt.  Haven't seen it actually happen but it's  a warning 
to "never" do.
  You need power to the D terminal when the key is on.  Power to  the B+ 
terminal/s at all times (if it has two, they're internally tied  together).
  If that checks and you're not charging (and checked the stuff James  
said) then it's loose belt brushe/regulator or possibly a diode but they don't  
tend to go unless you hook up jumper cables backward.  Alt is correct  when 
you can no longer spin the alt, by hand, against the belt's tension.
   Loren