unless your 4 post is a tractor type for an 01 series.. and a diesel at that.. being 12v.. it won;t work. IE... if it is a car solenoid.. it won;t work with the safety interlocked thumb switch.
if it is the tractor 4 post type. one small post to thumb button on trans top. one small post to key-on power. one large post to bat hot. one large post to starter..
so.. which ya got?