I'm going to go out on a limb here because it seems like most everyone does this at some point or another but never pays attention when putting the thing back together; like all of the pieces don't need to be there or go back together a certain way.......
The detent washer was installed with the tab in the wrong hole. Take off the knob, the nut, and the star washer. Then remove the detent washer. Turn the switch shaft fully counterclockwise and then reinstall the detent washer with the tab in the hole labeled as "6". Reinstall the star washer, nut, and knob.
VOILA!!!