Well done for your persistence fiddling with the switches .. I did a similiar repair on the rear wiper switch a while back ...

... and yep .. the cure for the melting switch/fog light issues ... is the same as for the headlights .... Just use the original factory wiring - to trigger a new relay and heavier wiring.

Tis a shame - that even tho they used relays to activate the foglight setup ... they didnt have the brains to use them on the high amp loads to any of the lamps ..

.