I have a 2003 Chevy Tahoe 5.3 4x4, I am having problems with my battery draining overnight. Found some info on BCM issues online. Had my wife take it in to local Chevy dealer to repair or replace BCM. Two days later I'm having the same problem. Because of my work schedule I was not able to take it in myself so didn't get a chance to ask questions or find out specifically what they did. Anybody else have similar problem or heard of this problem?