[Vwdiesel] blinking alternator light ??

[James Hansen]

diodes don't fluctuate as they die, they go foof and it's done.  Then 
instead of passing current one way, it can go either open, or conduct it 
both ways... which gives you a dead battery when the vehicle sits for a 
few days.

most likely it's a mechanical problem, such as the brushes getting worn. 
  they make intermittent contact when they are just barely long enough 
to touch the ring, and the internal voltage keeps rising and falling... 
so it's like a signal light, working, not working, working, not working....

How old is the alt Rolf?
-james

Rolf Pechukas wrote:
> hey all
> my 93 Eurovan DIESEL was doing something weird last night
> battery/alt light was coming on intermittently, faint, then bright,  
> then in between, etc
> tach would zoom up to normal, then falter, then die, then back up...
> I checked belt - fine, tight
> all electrical connections seem OK
> thoughts about what might be happening? it's been COLD here last 2  
> nights
> are these symptoms of a dying alternator?
> or am I not trouble-shooting hard enough?
> thanks for any thoughts