fm146 netural sense switch

[mean machine]

hello everyone i have a 89 ford ranger supercab 2.9v6 5 speed with bw1350 my question is is what is the purpose for the switch thats on top of the trans that is right behind the shifter what does it do cause mine is busted and i cant find one anywhere need a part number if anyone has one. i believe they call it a netural sense switch which i dont understand cause you have to have clutch pushed in to start so what does it matter if its in gear or does it up the idle or something when its in gear? please explane this too me lol and please help with locating a new or used one .thanks jason

 

[4x4junkie]

I think it's an emissions control sensor (changes the idle fuel algorithm or something when it's not in gear). If you can't find one to buy, then a junkyard should be a fairly safe bet (they aren't a common failure item).