I have a 99 Taurus with the 3.0 engine.
Today on a long trip I noticed that the battery 'idiot light' came on
under hard acceleration. Upon further investigation with a OBDII tool
while driving the vehicle I see that the battery voltage drops from a
steady 13.5V to around 12v only when the engine revs are increased to
around 4,000 or more. The idiot light comes on at these times.
This is indicative of failure of something in the charging system. Does
a knowledgeable mechanic here know if it is likely to be the voltage
regulator or the alternator? I'm not even sure if the Taurus has a
separate voltage regulator or if it's part of the alternator on this
Any advice welcome on diagnosing the faulty component.
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