Hi great cut away
And yes it looks galvanic , note the clean steel /stainless spring , I assume the rest will be copper Coated steel , and water /damp ingress is the electrolyte . This will definitely occur to all our cars given time . The swmitch manufacturer would surely have known this , as its basic bloody chemistry .
Again , nicely cut away
Regards
Andy

Again , nicely cut away

Regards
Andy