Trying to identify an engine part

[AHill100]

Right above the ECM on the lower part of the driver side of the block, right behind the main ECM cables, there is a sensor looking device which threads into the block. It looks like a temperature sensor or pressure sensor.



The previous owner of my truck installed a Carter fuel pump on the frame rail and wired the positive cable from the battery to this part and then to the pump. I removed the pump because it was causing problems.



It looks like this part was acting like a relay and the only thing I can think of why he did this was to have the relay open or close based on a temperature. Or, something like that.



This part has a red and black wire coming from it into a two-prong connector. They were serving nothing but the aftermarket fuel pump and everything works fine with these wires disconnected.



I have been all through the FSM and still cannot identify this part.



Does anyone know what it is?

 

[BDaugherty]

Oil pressure switch maybe? It is OEM or did he add an oil psi switch to send power to the lift pump only when the engine was running?

 

[sag2]

Should be the oil pressure sender. Short the wire to ground for about 30 seconds with the engine running and watch your gauge, it should stay or go to zero, and you should also get a chime.