1965 Dodge Dart headlight switch rod and knob.

Externally, the wiper knob is the same shape as the headlight knob and foes have a flat spot inside that fits over the wiper shaft. The knob has a set screw to secure it to the flat. The headlight knob and shaft is in one piece - you might have the shaft broken off and as you mentioned, the wiper knob jerry rugged in place. That’s why you’re having issues with it. I’ll take a look and see if I have an extra headlight knob