74 duster brake light switch

Redfish, I know where the reverse switch is and that it isn't relevant I was just making reference to how it operated, and I realize the purpose of the switch BUT what I am getting at is it possible the switch can be triggered by something other than a master failure, such as contaminated fluid or simply a failed switch?, if not then obviously I will require a new master, I am just trying to diagnose first before throwing parts at it, thanks