I have a 73 4/4. All of my switches have had problems, causing lots of different issues. I carefully took each one apart and cleaned it. Never a problem since then.
Just take your time with the disassembly. They are a bit fragile.
Paul
1973 4/4 "Henry A" 1953 +4 Flat Rad "Pug" 1984 Citoen 2CV Special "BeBe" https://morgan34.org/