mcshot

About 2 weeks ago my truck battery was found dead after a few days sitting. Battery was factory fresh 1 year ago. I now pull out keys but battery still dies in couple of days sitting. My wife noticed radio on with keys out of ignition but truck started after two days. Then it was dead again. While charging up I could hear the blower kick in. Shut the blower off and two days later battery dead. This has happened 4 times and shop won't exchange battery without testing as may be truck problem. Truck didn't have interior lights when purchased so suspect electrical gremlin. If there is something I know less about then wrenching it is electrical. Any and all constructive ideas welcome.
Thanks,
Mc