I Need Help!
 

I went out to start the C6 this morning and the key fob would not open the door. I unlocked the rear hatch pulled the rip chord and opened the door. Battery is dead dead. I know the last time that I drove the car that I left the car in reverse because I remember the horn sounding when I walked away from the car. Anyway I attached a battery charger to the battery turned it on and the horn proceeded to sound. I guess the computer thinks I am now trying to steal the damn thing. I can disconnect the battery from the car and charge it OK but then when I reconnect the battery I would imagine the horn will again sound. Any ideas? :smash:

Charge it until it's charged and then plug it back in. Even with the alarm going off, the fob should work by then and you can open the doors.

You should always disconnect at least one of the battery cables from the car whenever you connect a charger anyway. Other posts have said Chevy wants you to disconnect both cables.