Go to can tire and get some wider shrink wrap from the auto section...doesn't even need to be as long as you switch.
Slip it over your switch and shrink in place
And try good old contact cement. Scuff surfaces...Clean surfaces...brush contact cement on (not too sparingly) to both surfaces...let dry (as in not sticky/tacky to the touch) *keep out of dusty workshops/etc...*. When both sides are dry to the touch...position carefully...check position...press firmly and evenly. If that doesn't stick it....it wasn't meant to be.
