Headlight switch question

[gman]

My headlight switch had been acting up lately.....the dash lights would go out once in a while but jiggling the knob would bring them back on. Now they are gone and no amount of jiggling will light up the dash. Does the switch have to be grounded or something for it to work? I"m wondering if the switch has some rust on it causing it not to work. Headlights work fine and the inside cab light works fine when turning the switch for the interior light. Is the switch toast or is it just a bad ground? Thanks for any help.