On some vehicles I'm told that the charging bulb - if it blows - can cause this fault. The alternator gets its exciter current from the bulb circuit - it the bulb is blown the alternator does not generate much power.
If the bulb actually lights then it may well be the alternator.
A bulb is much cheaper than a new alternator...
http://www.howtomendit.com/answers.php?id=292574
Good luck...
Peccavi
January 2010
alternator no good
steray
January 2010
Automatic Answer
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