2000 Dodge Durango Won't start

I have replaced the starter, checked the relays, and my durango will not start. The battery is fine as well. When I turn the key, the lights and radio come on, but there is nothing cranking. There is a small click sometimes, but for the most part it does nothing. It would do this intermittingly in the past but now it is nothing. In the past we would take out the relays and put them back, or move the gear shift up and down and that would work sometimes, but not now. What else could be wrong?