96 Windstar won't quit running

My van will not always shut off when I turn the key off. I have already replaced the iginiton switch and that seemed to work for about 5 days without any problems. Now I wake up in the morning with a dead battery. Could there be a problem with the lock cylinder not working right? because by the wiring diagrams theres not much else it could be.


Thanks
James

Works for about 5 days? Where are you getting these switches?