My voltage is reading at 15.8 what can it be ?
Asked by Calvin Dec 04, 2020 at 03:01 PM about the 2004 Pontiac Bonneville SLE
Question type: Maintenance & Repair
My 2004 Pontiac Bonneville sle is reading a voltage of
15.8 and when I drive it goes up more once I go pass
60mph the check charging system light come on when I
slow down it goes away what can be the problem? I have a
new battery and I order a new alternator but someone told
me it may not be the alternator
4 Answers
beatupchevy answered 4 years ago
I would find the problem before driving it , you could fry something .
Sounds like the voltage regulator is bad. The voltage regulator is inside of the alternator and not replaceable separately. So I think replacing the alternator will solve the problem. Hope that helps! Jim
Some vehicles (like my 97 expedition) the voltage regulator attaches externally to the alternator, but it definitely sounds like you have an overcharging issue which is most likely due to the voltage regulator. If you can get it separately it will save you some money, but if its internal to the alternator you'll have to buy the whole alternator.
Older Ford Products did have an external voltage regulator long after GM. GM stopped using external voltage regulators in 1973. A few years earlier on Cadillacs and vehicles with a trailer towing package. Jim
