Hello everybody. New to the site and i have a very odd problem with my 99 Jimmy 2dr 4.3.
Ever since i bought the thing 3 years ago i noticed the voltmeter never read quite as high as it should. It was always a little under 14V but it never really bothered me because the Alternator and Battery were brand new( Alternator was a brand new one and not remaned) I have been driving it for 3 years now and have only had to put a wheel bearing on it, and another battery.
I noticed about 3 weeks ago that my volt meter would "flutter" at times and my lights would dim a little. I thought either battery or alternator were going, so i tryed a new battery, no change. So i swapped alternators with my fathers 97 blazer, same thing.( my alternator on his blazer read 14.7 volts, so i take it its still good) The gauge still remains a little under 14 volts at most times, other than when the guage flutters which it will drop to about 12 volts and jump back up.( i tested the battery with it running and it with intermittently go from 14.2v to 12.3 and back up again) Battery light will sometimes come on to. Also, all the time, when i use my turn signals, the gauge will drop a little in sync with the signal relay(turn signals dont use that much juice)
I was told to check to see if it was a certain accessory drawing too much power, but even with all accessories off, it will still do it. Anyone have any ideas? Any guidance in the right direction would be appreciated.(sorry about the novel guys, lol)

 

I would probably check the wiring to your alternator.

 

Wires goin to the alternator are in good shape and clean. I made sure of that when changing the alt because i was hoping to fix the low reading.
I was wondering if there was any other system in the truck that would "cycle" other than the ac because thats what it seems like its doing. Im goin to check my grounds off the battery today and see if one of them are loose or dirty.

 

Yeah, I would probably check the grounds then past that I'm not sure.