Billy joe

1999 chevy suburban 1500 LT 350 auto 4x4 radio comes on with out keys in truck.I have taken it to a couple decent wrenches and they can not figure it out.They also could not find BCM after calling several dealships asking where it could be.We checked under the hood behind the radio behind the glovebox under the consol under the seats.....Has anyone else ever had this problem? Do I need a priest? This truck has no rust 165000 and in mint condiction.Tired of a dead battery twice a week.