Headlight switch - 75 Duster - Stumped...
Doh! I got it.
Terminal B2 (battery 2) is a separate 12v input, from a fused source. When I check continuity from B2 to R (parking lights) and also B2 to I (dash lights) with the knob pushed in (off) they are open, however when the knob is pulled out to the parking light position and the headlight on position I get continuity from B2 to both R and I.
I wasn't using a separate 12v source for them...
Never mind :)