93 Villager was running fine. Parked, wouldn't turn over. No click, nothing.

What is your question?

Stranger with tools said "I know what it is - It's your (3rd) wire, the one that activates the switch." I wanted to see the connection but he said to get in and try it. started right off; problem solved but returned 3 days later. I can't find the same wire, have tried to tighten all connections, but it won't turn over. No click, nothing. What am I missing? Thanks for any help; count on my reliable vehicle . . . thanx . . . tanck. 08-07-2015.