The light switch on my 64 is stuck in the closed position. Nothing I do seems to free it up. The switch has a little ****on on the backside of the dash that you can press in and pull the knob at the same time and that is supposed to enable you to remove the knob. No amount of trying that tactic works. I can't change the switch until I can remove the knob, at least I don't think I can.
Normally that little spring ****on is used by pulling out the headlight switch knob to it's fullest, depressing the ****on and slightly pushing in the switch knob and gently pulling the knob and shaft out of the switch. But if you can't get the knob out the ****on is going to be of little help, I think. You can always cut off the knob with a thin Dremel blade. Of course, you will need to buy a new shaft and knob (as getting that bit of shaft out of the knob after cutting it off would take more effort than a new knob would cost. Maybe someone will have a better idea that utter destruction, but I like destruction.