Alright, so I finally managed to find the oil pressure switch. It turns out it was hidden behind the thermostat which wasn't mentioned in the service manual. So, I had to remove that too which was a massive pain in the ass. The wire going to the switch was cut. I'm guessing it was an accident by the previous owner's mechanic. I'm not sure why he didn't just buy a new wire harness as they are not that expensive anyways. So, now I'm ordering a new wire harness and I guess I'm going to replace the old oil switch anyways since I already have a new one.
Also attached to the wire