Cadillac Repair: 1991 Brougham engine draining, negative battery cable, amp meter

Question
I just bought a 1991 Brougham 5.0, and the battery died, and even after we jumped it, it died again.  I took it to a mechanic, and they checked the battery and it was fine, so they thought the alternator was fried, but when they replaced it, they said the same thing was happening.  He told me that something was pulling -19 amps or something like that.  He recommended getting rid of it, but I've already come to love the car, and I'm hoping it is something fixable.   Any Ideas?

Answer
You need to install an AMP METER between the negative battery terminal and the negative battery cable and see how many amps it is drawing and start pulling fuses and relays one by one until you see the amp meter drop to approx 1/2 amp. Then let me know which fuse or relay is causing the problem