Maybe this has been posted before, not sure so I thought I would share.
I recently picked up a second console with a defroster switch and choke plate that I needed for $75. I figured a spare console would be good anyway. When I got home I realized the switch was frozen. I put some lube in it, freed it up and cleaned it with electrical spray. Tested for continuity and nada. I recently rebuilt my headlight switch and wondered maybe this was similar. Sure enough it was.
With a small screw driver, gently pry each side out and slowly lift it out. Be very careful not to lose the small plastic tip and spring. I did! I had to rob one from an extra defroster switch from my old 73 parts. You have to gently bend the side metal tab holding the metal rocker in place to get it out. Just bend one of the two sides.
Clean it up and assemble. Gently squeeze the metal side back in to hold the rocker in place. When putting it back together, push it together flat and it snaps right into the housing. I tried at an angle first and it bound up. Now is a good time to check your bulb and clean it up as well.
Before:
Apart and cleaned up:
Together (You can see the black plastic tip pushing against the rocker. Don't lose it.):
Working: