2004 gear selector problems

[bbchevy]

2004 chevy 2500 express van with auto and 5.3L. Van will not start when gear selector is in the park position. if in neutral it will start. also, the selector does not follow the path of the shifter. if you pull it down to say first, then back up to park, it will say its still in first... but its not. And that goes for any other gear its put in. it will stay there. it all mechanically works fine but electronically it does not. Now its beginning to not start in neutral.

Neutral safety switch on side of tranny? thats my guess. but before i go digging into it, i would like your opinion.

Thanks alot guys,
-Scott