One wire alternator problem

I would agree it was the ballast resister but I'm wired in on the bulk head side. The wire that used to attach to the alternator is not used. Power used to go through the car to the battery. Now it comes from the battery to the car. I hate wiring. I've checked every connection from the battery into the car and back out. 12 volts without the car running all the way to the ballast resister. Thanks for your in put ChrisPerry