Although you did a lot of good testing, I think you still had "one assume" which is usually bad. Further the "assume" is potentially wrong, literally and figuratively... :-) It is more likely that the blue and green are not connected to anything at least during your "voltage check" which means your .002v is just "air leakage".... like holding your probes in mid air. Just a guess.
As suggested in general, measurements need to be reference back to a KNOWN ground... this is true for both voltage and resistance.
I suspect you might find that the red and blue are open at "neutral setting".
Not sure of the type of switch and how the wiring is down, but if you can disconnect it from the wires easily and take some resistance measure to check which contact make which contact during "neutral-nothing, in, and out" you should be able to deduce more about what you are up against... hopefully.
My guess is that the green and blue go to the motor (very low resistance as in almost 0). When you move the switch one way, one set of voltages are made from one side. When you go the other way, some how those are reversed.
PS... oops corrected the colors
final oops, yes, agree that the red path to switch from the fuse is the one in "question".... assuming nothing is rattling around in the switch itself.