2004 Chevy Suburban A/C will not shut off or turn on

Hello;
I was driving my Suburban here in Florida and a daily storm shower had just came through I was driving with the A/C on and when we stopped to do some shopping I turned off the ingnition and heard my A/C still running the key was not in the ignition. I waited about 5 minutes before doing my shopping. About 45 minutes later, when I tried to start the vehicle, the battery was dead. A/C now only works in the rear but not in the front. At highway speeds the A/C comes on in front very low even though the setting is on high