Stopping wipers

I had the same issues with my 66’
Every thing was rebuilt and made like new and still issues. Even harness was brand new under the dash. It turned out the switch needs to be grounded. Once I properly grounded ( the paint acted like an insulator) it worked great.
I get yours may be original. So surface rust or corrosion on the switch could be the issue. And yes the circuit breaker is in the wiper switch. The circuit breaker is not replaceable.
Keep us posted.
Joe