I have a 05 Avalanche that ia driving me insane. Something is draining the battery every 3 days. I can get it jumped and everything is fine until I go to get out. With the key out of the ignition everything in the car stays on. The radio, the clock everything. Same when I open the drivers door. I literally have to walk around the truck and open every door until it all shuts off. I need help figuring this out before my husband puts a kill switch on it. Also I don't know if this is related or not but the heated seat on the drivers side cycles through even when you hit the buttons to turn it off.

 

You need to put the battery on a trickle charger or it will die out, running dead all the time. Something is drawing current, and you have to find out what it is.

 

If the radio/clock stays on when you open the drivers door then you either have a broken wire in the drivers door jamb conduit or a bad drivers door latch. That's where the switch is that tells the computer to turn off the retained accessory power relay. Usually that relay is timed out after 10 or 15 minutes. So that alone should not kill your battery. You may have something else that is draining the battery. Or maybe just a bad battery.

 

look and see if vanity mirror light is stuck on.