Hi gold. Welcome to the forum. If the new switches fix the problem, even for a short time, look at the wire terminals in the connector to see if they have been overheated. The plastic connector body will be melted and some of the wires may be stiff and not as flexible as the rest. Overheated contacts in the switch will cause the initial failure but it will damage the terminals in the connector too. They will lose some of their tension and develop high resistance connections. Any resistance leads to more heat buildup and a repeat failure.
The overheated terminals must be cut out and any melted parts of the connector body must be cut away. New crimp-type terminals can be used and plugged in separately but also solder them to the wires for a better electrical connection. If the wire is stiff or corroded so badly that solder won't adhere, cut off about 4" and splice in a new piece of the same diameter. The wires must be shiny for a good connection.