Take the belt off and spin each pulley component by hand to find the worn out bearing. Your mechanic should know to do this. Not sure who you are working with. The bad bearing will offer resistance to turning compared to the others.

Are you losing coolant or overheating?

Don't mess with that switch until you confirm you have 12 volts at one or the other pins in the connector versus chassis ground. If you are not getting power to the cutoff switch then you have other problems.