2000 Dakota

Possible Ignition switch faulty. You need to investigate closer to see what it is that you are hitting. Look under dash or remove any panels you can to access that area. Don't b too invasive by touching and grabing wire harnesses. The reason is you may cure a bad connection or shorted wire by moving it. This makes it hard to duplicate again.
Carefull look and wiggle as few wires at a time as poss. I should mention to have the neg. Battery terminal already loose in case of electrical fires you can remove the batt cable quickly. Only a precausion. You probably need an ign switch. Look for overheater connectors.

Already replaced ignition switch did not solve problem

You have to investigate what is being struck under the dash to finally turn to engine off.