I have A 2000 blazer 4x4 4 door 4.3 with 170,000 miles. just recently put in new battery, got in this morning and had NO POWER to anything.I jumped the the battery and it started it is reading right at 14 volts when running.......the other day got in and started, the air bag light stayed on until restarted.....can any one help!!!!!!!!!!!

 

found out the previous owner had a expensive stereo system in it. have been told the alternator might not be charging at the right voltage,but i have no battery light or check engine

 

Is their a subwoofer or amp in it?
Or amp wire?
I have one in mine it sometimes drains the battery out.

 

yes but its not hooked up to anything, removed the stereo that was in it and seems to be doing better but still not sure will have to wait till morning

 

Do you have a DVM to measure alternator voltage output?
Alternator charging at 14Volts sounds good.
Measure the battery voltage with engine running (should be 13V +),
and engine off (should around 12V)
Does your 4WD work OK?
If you have a DVM that registers current, measure across the fuses with engine off to find what circuit is drawing the highest current.
Otherwise, try removing the fuse for the radio overnight.