frustrating electrical problem

we have been battling an electrical problem for sometime and desperately need some advice.our van starts only sometimes and even then we have to turn the key 3-5 times before it will turn over. when we turn the key just to have the dash come up we hear a clicking and sometimes will hear other electrical things engage. other times it is just the clicking. we have replaced the lock cylinder and the ignition switch. we have tested the starter and the ignition coil. they test ok. we have cleaned corrosion from multiple places. after some of these things were done it would be ok for awhile but always goes back to being stupid.we have had a diagnostic run on the van and it shows no problems. any advice or ideas would be greatly appreciated.

If you haven't already pull both battery cables and thoroughly clean the inside of the cables with a solution of warm water and baking soda , best thing to use is a old toothbrush ,then clean and dry, do this even if it doesn't look like it needs it . Sometimes you can get an almost invisible high resistance coating on the cables. Get a battery terminal cleaner and rough up the battery posts and then tighten cables . Also you might want to get the battery load tested at the nearest part store while disconnected.

What did you do to make it work for a while? Are you having any intrument cluster problems? Have you checked the main ground connection coming off the battery at the engine block or frame?

What year is the van? depending on the year and engine, alot of
vans had a problem with the starter solenoid contacts. They would do
just what you are describing. The starter may still test good.
The contacts are available from Dodge. Contact you local Dodge dealer, tell
them the year and engine, and see if these parts apply to your van.