Will not crank sometimes

When additional lights and circuits are involved, that is more than just a starter circuit problem. You have to look at what they all have in common, and one of those things we see real often is a bad connection at the under-hood fuse box. Follow the smaller battery positive wire to that connection, and be sure that is clean and tight. While you are at it, follow the smaller battery negative wire to the body and be sure that one is tight and not rusty.