What is the function of the oil pressure sending unit behind the oil filter? What happens if it doesent work or the wire to the unit becomes disconnected?

I thought the sending unit was below the filter on the back of the block! The stuff behind the filter is the water temp units. One for the gauge one for the ECU.

Yeah, I know where it is I just need an answer to the question, thanks.

Oh sorry about that. I would imagine that the light just wouldn't work not sure though.