When ever I park the truck after going to work or say coming home from work I put it in park turn the key off and get out with my keys in my hand and after about 30 seconds the horn sounds and the truck locks itself. It did it to me one day and I had to have the wife bring my extra set of key because mine where on the seat. Have I messed something up or changed a setting? I have looked threw everything on the DIC and cannot figure it out. It is kinda dangerous it does it every time I shut the truck off now. Any ideas?