I'd like to open this forum again. I have the exact same problem. I have a 1990 Jeep Wrangler and purchased a 1994 gauge cluster for the fuel, water etc.. I used the wiring diagrams above and it didn't work. Only the lights would come on. So I'm guessing illumination and ground are correct. This is what I did:
1990 wires to 1994 gauge
pin 1 coolant to pin 11 coolant (diagram says pin 12, no wires coming out of plug)
pin 2 gauge fuse to pin 2 ignition feed
pin 3 ground to pin 13 and pin 1
pin 4 fuel to pin 6
pin 6 oil pressure to pin 9
pin 10 illumination to pin 7
pin 12 illumination to pin 8
Thank you sir, trying to re-wire my dash and I wanted to reuse most of orginal harnes like for fule power ground ligt dimmer etc I could run new wire for oil and water IF i had to but If I could just change the sensors and use same wires its easier.
What guage? Are you talking about the wire guage size? If you are the guages can be run with 18 ga. but the lights for the guages depend on the current draw of the bulbs and how you wire it. I would recommend 14 Guage if they are incandensent bulbs.