I am a proud owner of Landcruiser GR71. I am also close to this upgrade, and here is my progress:
After page B-15 from the manual. as I am after the wiring to the oil pressure sender. My car comes with light only (single wire oil signal sender), and I am replacing the cluster with one with tacho and oil pressure gauge. Everything working except the oil pressure gauge. I got the 3 wire oil pressure sender ready, I just need the wiring diagram
I have added the pictures above: the old cluster does not have rpm or oi pressure gauge. The oil level is detected by only the red light via the single wire oil sensor sender in the engine bloc. The 2nd upgrade cluster has the rpm, voltage and oil pressure gauge. Now after connecting the latter, everything works except the oil gauge, so I got the original oil pressure sender (has 3 wires), and this I believe need to be hooked correctly to make the oil pressure gauge works. If anyone has the concerned wiring diagram, that would be awesome . I guess it should be somewhere in page BE-15 manual.