hi. i havent been to the forum in like a year, sorry, i just had a bunch of stuff goin on, but anyways, im havin a funny problem with the voltage in my blazer.
mind you, i've been a 12volt installer for the past 12 years so i know for sure it is somethin im over looking.

anyways, its a 2000 blazer 4x4.

the other night i was goin to the store and noticed my battery light was on, and the volts on the dash were reading 9.
the volts on my screen were reading 10 - 11.50 (which is what my meter reads also)

so it was a optima yellow top, which was 6 yrs old, and the last one i had lost a cell and the same thing happened, so without a thought, the next day i got a new one.

i put the new one in, started the truck, and it was reading the same, as the old one, and yes the battery light was on.

so, with the truck still runnin, i went back under the hood to make sure i tightened all the terminals and to collect my tools cuz it was starting to rain. like 2 minutes later, when i went in to shut the truck off, the battery light was off, and the gauge read 14, which is what it always read. so cool, right?

about a hour later i was about to go and get an oil filter, and the gauge read 9 again.
so i did the same thing as before and just let it run, but it never moved.

it starts fine, and i can drive around, but as youd guess, the wipers and windows etc...work slow due to the less voltage. but the voltage never drops below 9 (factory gauge) which in reality is probably just at 12

all the terminals are clean, and the ground is fine.

i've been super busy at work, and im kinda burnt out with all the 12volt work, so im sure im over looking something silly, (i hope) i dont wanna be chasin fusible links around

do you think its somethin as simple as the alternator?
would the alternator charge, but for some reason , only to lower voltage?
i know i should know this, but i really hate 12volt and dont wanna do it anymore lol

**also, when i rev the engine, it doesnt increase the volts.**

 

Sounds like your alternator is not putting out anything... I would get the truck to an autozone or the like and have it put on their charging/battery analyzer.

 

thanks for the reply! well it seems like the alternator is limited to charging at 10 or 11 volts. i havent had an alternator die on me in a long time but from what i remember, they die and a while after your battery dies. but i can run the truck all day and it wont die

so my other question , and im sure youd know this kyle, is

i have a 200 amp alternator i took out of my 94 s10 blazer when i got my 2000.
the alternator in the 2000 is a one wire alternator, and i remember the 94 had 2 or 3?

now when you look up parts for the 94 vs the 2000, the alternators ARE different part numbers, but in both manuals, under the testing the volt light section, it says to take the wire off of pin f etc......

what im askin is can i take the big alternator i have from my 94 and put it in my 2000 and have it work? even though the 94 wasnt a one wire alternator?

probably not huh?

see in the 94 i dont know what the other wires in the connector were for.

 

Will it even bolt in..? I would have to look at wiring diagrams to see what each wire is.

 

well, two of the three mounts will bolt in, but the alternator would be upside down compared to the one thats in there now.

i have the alternator out already i guess ill just bring it to autozone.

i think im just makin a bigger deal out of this than it actually is, just because im used to my 94, where every problem i had, was always a troubleshooting problem and could never be somethin easy lol.

 

I am having the exact same problem

 

in reply to bradley.....yea Its tht alternator that's exactly what mine did

 

i just got back to autozone and my alternator failed the test with flying color and it was a brand new one and it was a good one a Delphi

 

i replaced the alternator and its working fine but still not charging the battery any ideas please help me

 

Wiring all intact? Is the PCM telling the alternator to charge?