ok Well after looking at that sheet the only thing I can figure out it that once you shift into reverse the lower part is forced into contact with the upper part by hitting the transmission case (specifically the shift tower). Does this seem correct? Is the lower part an actual switch like a( mid 70's chevy) brake pedal switch?

Thanks for posting the pics!

Brian Moore
1949 3100 5 window Deluxe
"Today is better than yesterday, but not as good as tomorrow"