I am wondering where I should look next, replaced the battery, the starter, sparkplugs and wires. Sometimes the van starts up, then other times when I turn the key I hear the clicking sound. There are times when I am driving and all of the door locks will make noise as if they locking and unlocking to stop this I push the door unlock lever.

 

Determine if the click is the starter or the starter relay in the PDC (fuse box) or something else. Turn the ignition to on/run then turn it slowly to start and have someone out front listen.

If either the starter or starter relay is clicking that means the PCM is grounding the relay. You're then looking at possible battery cables or cable ends or starter connections and wiring between. Before going there, new battery or not, make sure the battery is reading at least 12.3 volts engine off and you're seeing 13.5 to 14.5 volts at the battery posts with the engine running. Turn everything on and the voltage shouldn't drop more than a tenth or two then recover.