Self Starting

Why would a 2006 Kia Sorento, when I have the key in my hand, I'm standing outside the truck pressing the lock button several times, try to start itself? I put in a new crank sensor, timing belt and components. I checked and rechecked everything several times to make sure all work was done correctly. My work should have had no impact on the problem I'm having. Also, the fuel pump will not engage but the relay is getting fire. Could this problem be the ignition switch?