1997 Cadillac El Dorado SOMETHING IS DRAINING THE BATTERY

For it to discharge the battery in 5 minutes, it is a large draw. I would look for something obvious for starters. Something like a stuck seat switch, or faulty alternator. Was the drain present before the alternator was replaced? You could almost crank an engine off and on for 5 minutes and not fully discharge a good battery. Something of that size, you would almost not want to connect an ammeter in series, as it would blow the meter fuses. You might be able to connect a test light in series, and pull fuses looking for the change. Upon looking at the schematic, the windows circuit breaker in the LH underhood fuse block, powers both the windows, and the sunroof. Check this circuit breaker. If it is warm, it may be tripping due to a short in the circuit, or a stuck item like a switch.