Not sure what you mean by greasing all my contacts, but if you are putting dielectric grease on your ground terminals between the body surface and the connector surface, then there is your problem. dielectric grease is an insulating compound to be used for sealing and lubricating purposes. You should only put it on the outside of the circuit after a clean surface to ground connection has been made to help seal the connection from outside elements that might cause problems i.e. water, oxygen.

My oldest brother once "redid" all of the wires in a trolling motor using Liquid Solder and wondered why it wouldn't work. He thought because the name "solder" was in the name of it, that it would conduct electricity!

Put over 1000 miles on her last week, calling this problem solved.
This thread saved me hundreds of dollars in troubleshooting costs!!

Thanks Derf!

You're quite welcome. What was the solution?

Took the battery out and cleaned all the connections, including the chassis ground.

I also invested $9 to have an ignition relay on hand if that turns out to still be a thing, but so far it's been clear sailing.

like I said in my first post --- go for the simple stuff first