i have loose cables on my battery. sometimes i have to wiggle them to get my 97 chevy blazer to start. a few days ago it wouldnt work so i changed the starter. then i realized that although my veh was in park it was rolling. after i changed the starter it wouldnt start.i hit the automatic gear shifter with both hand thinking it was stuck and it went into ppark and started. it has happened again and hitting the gear shift wont work. what could be the problem. the install instructions on the starter said something about a clutch safety switch being engaged?