New alternator not charging

I am having trouble getting my alternator to charge. It started a few days ago. Everything was fine, had been driving the car to run errands in the morning. On the way home the charging light came on on the dash. I knew that was not good so I immediately headed for home before the car died. So I get home and check the voltage, its down in the 11v range. I hook up my battery charger to bring the battery back up. Start the engine again, check voltage right at the big terminal on the back of the alternator, still only getting battery voltage, not 14v charging voltage. So I suspect a bad alternator. Call the closest auto parts store, AutoZone. They ask me if I have a Bosch or Valeo alternator. It's Bosch. They have it. I go get it, spend the next couple hours replacing it. BUT the one they sell me is different. It has an air duct on the back of the housing and a rectangular plug instead of the oval one mine has. Well I wasn't giving up at this point. Made an adaptor to make the plug work so the single blue wire which was going to pin 1 in the oval plug also goes to pin 1 in the rectangular plug. Start it up, still not charging! So after more testing and searching online I find that this wrong alternator scenario has happened to others before, and I find out I need to request an alternator for a 2003 Z4 to get the right one without the cooling duct and with the correct oval plug. So I do that yesterday, get the new correct alternator on, start it up, still not charging! Now I am really stumped. What could be causing it not to charge? Sure it could be a bad alternator since they are all rebuilt. But how likely is that? The one thing I cannot figure out is if I am getting the correct voltage on that single small blue wire going to the oval plug pin 1 on the regulator on the back of the alternator. I get about 9 volts there with the key on and with the engine running. Is this correct? Where do I go from here? I am not a novice when it comes to vehicle electrical systems but I have never run into a problem like this before.

Any suggestions? I've been trying to get the online WDS diagrams to work but so far I am struggling with Java errors.







Thanks,

Jeff

2004 330 Ci with a 2003 Z4 alternator!@