I used my test light on the switch with test light clipped on #1 hot wire/spade and probe touched to spade 2 & 3 but not sure this helps determine if the switch is bad or not:
With switch in off position spade 2 and 3 both light up. With switch in second position which operates the parking lights (which work), spade 2 does not light up but spade 3 does. With switch in third position for the headlights (which don't work) spade 2 does not light up but spade 3 does. Not sure what all that means.