Charging light stays on

HOMER HUSTON

MEMBER
GMC SAFARI

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

1 Reply

CHEVY22

MECHANIC
1,375 POSTS

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