Gearbox rebuild

[parasys]

Hello all
I have just completed a rebuild on my 2010 GLX-R MN gearbox. New third gear synchro and hub, new bearings and an extreme outback clutch.
Job went well given that it was my first gearbox rebuild, truck is now mobile again so the family is happy. I now own a press, bearing splitters and custom made tools to remove 5th gear.

Question
The "gear position switch assembly" is the forward most switch on the drivers side of the box. It is similar to the reverse switch but the reverse polarity. I broke mine!!!

I am having trouble sourcing one in Darwin and am looking at other alternatives, LC70 appears to have a similar switch but I havent checked the polarity yet.

My question is - what does it do? I have plugged the hole up at present and have the switch plugged in and sitting inside the car, I cannot find any difference in chracteristics with the switch open or closed - do we even need it?

Ideas would be appreciated.

Happy to pass on any advice, experience etc about the rebuild. I have some photos for reference should anyone need it.