Charging light stays on

GMC SAFARI
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HOMER HUSTON
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2002 GMC Safari AWD 70.000 miles -- Charging light stays on most of the time -- battery voltage open circuit 12.8 v -- alternator output 13.9 v at idle and 14.2v at highway speeds-- this condition has persisted for 3 months with no reduction in starting power or battery function -- drive belt is new in last 4 months -- battery voltage is at 12.8 v after sitting over night -- voltage does not drop more than normal with lights on and engine off or during starting. Do not notice any interior light dimming that would be found with a bad chassis ground. Everything seems to be normal except the light staying on
Oct 22, 2007 at 5:51 PM
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CHEVY22
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sounds like you have good output from the alternator , there were some problems with these vans like you are having with the pcm , the charging system sends a signal through the pcm and it decides if the voltage is correct or incorrect , when incorrect the bat light will come on , this sort of problem needs to be diagnosed properly , ive seen guys throw a pcm on a van an not fix it and it ended up being a reflash to the pcm or an pin that had walked out, the best advise i can give you is to let the dealer check it out or atleast diagnose it

jim
Nov 3, 2007 at 8:37 AM