So this is the deal, I have a 79 sd. When I jump start the car and its running. I disconnect the leads from the battery. At that point I put a ohm. meter to the positive and negative. It reads 00.0 should it read around 14.0? When I test the battery it ranges from 9.0-12.0 volts.
Would this be the alternator causing this problem of a dead battery?

Thanks!!!