97 thunderbird charging problems

A friend of mine has a 97 Thunderbird. The battery stopped taking a charge. He changed the alternator. After putting in the rebuilt alternator he is having the same problems.
Also dissconnected the battery cable when running and it died immediatley. All the wiring and connections check out. Even went as far as putting in the new fuseable link. Besides being possible that he got a bad alternator. Does anyone have any suggestions of what it could be?

icant remember which one but theres a fuse in the underhood fuse center thats not labeled for charging system had problem on my car till i printed out wiring diagram

It's fuse #9 (60A) thats in the Power Distribution Box and is labeled Ignition Switch. With a fully charged battery and the key in the Run position and the engine off, check to see if you have 12V at the LG/R wire in the 3 terminal connector on the alternator. If you don't have 12V then the fuse or switch are suspects.