Well I just picked up a 96 blazer for my mail route.....it has a brand new battery but the volts are reading low....ranging from 11-13ish...now my girlfriend has a 97 ls aswell her gauge reads a little above 14 as soon as you fire it up.....so Id assume my alternators going to take a dump on me .....whats a good method to test it instead of just assuming (maybe my gauge is flaky hell it didnt even work on my last blazer)
any help would be appreciated!
thanks
JOhn

 

Autozone!!! theyll test it for free. or any service center should check it for fairly cheap. Other wise just take a volt meter and connect to your battery, start the car turn on all loads(i.e. flashers radio a/c all lights, etc etc...) run in at about 1500 to 2000 rpms and watch the volts on ur meter, thats what we would do at the dealership! It should be pulling anywhere from 11.8 to 13.2(again thats what we would do at the dealership i worked at!! The only bad thing is you cant tell if the diode pattern is good. Youproblably should check the amps it has while doin that too, and compare that to the spec if your dvm can read apms that is.

 

good thinking I always forget about the zone thanks

 

just changed my Altanator today. what a bitch, spent most of the tiome getting the old one out and the new one in (thank god for pry bars and rubber mallots). That plus the 110 degree heat index made it fun! of course I mad a rookie mistak and forgot to put the belt back on, had to as a random guy in the Walmart parking lot (where I pulled over when I noticer my A/C was blowing hot, my engine tep was spiking, and I had no power stearing) to help me get it back on.

 

You can test em by your battery gauge........make sure the truck is off, turn the key to on, if you are under 9 volts on the gauge it usually means the alternator is bad.

 

when the car is running, take a screwdriver and touch the metal end to the nut where the 12v connection is connected. if you feel a magnetic 'pull', the alternator is charging your battery