2004 gmc yukon new alternator and volt meter still not at regular range

Voltage draw down found!
1) repaced bad battery
2) rechecked voltage draw still showing 12 volt drain with all under hood fuses, relays, and interior fuses and relays pulled.
3) Computer was the 12 Volt drain, & had to reprogram itself.
4) gave the new battery a good long charge, reinstalled the battery into the vehicle.
5) Hooked the battery up, pulled the keys out of the ignition, close and lock all doors with auto door lock. Waited minimum of 20 min so the computer would go back into the sleep mode.
6) after 20 minute wait, rechecked the voltage draw by removing the neg battery cable from the battery, hooking volt meter + lead to battery cable end, and neg lead to battery neg post, nothing showing or zero reading.
7) Hooked the neg cable up to battery, started the truck and let the engine idle to normal run temp, then fast idled 1200-1300 rpms for 2 minutes, then drove the vehicle for 5+ miles and alternating speeds. All appears back to normal now. Alt showing 14.2 to 14.4 volts, and no other problems.
After all of the afore mentioned, my problems began with a bad battery cell, thus caused my computer to have the memory reset.Until the computer was reset, I had a 12v continious draw down! I got this info from a repair manual, that I purchase sometime ago. Thanks for your alls help........EJB