Because no oil light for pressure on Rangers, the gauge is on/off so same as a light
Ground the wire at the switch and light should go out, if not then problem is in the dash, assuming your wire test was good
If light goes out then you got a bad "new" switch..................................or, clogged oil passage tube
For the later, disable spark, you want a NO START
Remove switch and put towel around the hole, crank engine, oil should of course come out of the hole, and if plugged it should clear it, if no oil then it is good and plugged, lol.
I think I have a ground somewhere that is melted through or not making contact. I tried grounding it out at the sensor and the cluster itself I can make the lights dim but it will not go out. What is the best resource to look up wiring diagrams and ground locations