So, i've become a little curious on how this switch works, my buddy is telling me that it's directly connected to my oil pump via direct passage way through the block. Any one wanna explain to me how these things work?

 

oil pump sends oil up the main channel to the filter. from the filter it spreads through all the galleys. oil pressure sending unit is at the top of an oil galley. it has a spring/diaphragm that deflects under pressure from the oil flow, and outputs a variable dc voltage signal. pcm reads this signal and translates it to a position on the gauge.