Working on an 02 Pontiac Grand Am with 3.4l V6. When I check the battery voltage at the battery while the car is running all I get is battery voltage. I replaced the alternator thinking it was the culprit, and made sure the battery was fully charged. I had the old alternator tested twice, and both times it tests good. Is this a common problem, or do I need to do a bunch of wire chasing to find the root of the problem. I'm not much good with wiring, but with good directions I can figure it out. Thanks.