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.
My car has high mileage and the switches have been apart many times, so the contacts are worn and the plastics well chewed up. The rocker switch in front of me shows signs of being glued together as there is a crack in the side. I think several of them have got to the end of the road!
