Originally Posted by jedwards242000
put the red from dmm on the red battery cable the black from dmm on the black battery terminal and start the car see what the voltage is if its 13.6-14.2 then most likely your alternator is ok. unless your having a voltage regulator issue from the alternator. then you need it bench tested
+1, also test it at ~2500 RPMs, with all loads on (blower motor/headlights)
Bench testing is best, but this works as well...