You need to post a good clear photo of the rear of the cluster. If you need to, overlap two photos. "Generally" the oil gauge (Ralley) equipped clusters have a 3 terminal fuel gauge. 1 terminal is switched 12V "ignition run" wire, 2...is output of the IVR unit inside, which jumpers over to the oil and temp gauges to feed them power, and 3....the last terminal goes to the fuel sender
How did you replace it? The IVR on those is built into the fuel gauge. To replace it, you much figure a way to make it "safe" and then mount an external one. They have a ground terminal which may not be obvious, and on that note, run a separate ground pigtail from a ground pooint on the cluster, and bolt that to the column mount/ dash frame. The lighting grounded trace goes to some of the PC board mounting screws
To check the gauges, jumper 12V power to the proper harness connector pin and of course ground. Rig up some test resistors, you can use the fuel sender if nothing else. All three gauges (oil, fuel, temp) use the same sender ranges. You should show about 5-6V or pulsation at the power terminal of all three gauges.
Since none seem to be working, check continuity of all three through the gauge terminals, check that you are actually getting power and ground, and then if that is OK, you have a bad or mis-wired IVR
