Gauge Cluster Issues/IVR

All 3 of these thermal gauges are 20 ohm gauges. Check fuel gauge at posts A and S. Check oil and temp gauges at posts I and S ( they dont have a post at A ).
The limiter is chassis grounded via a slither of metal on the back of the gauge against a unpainted spot in the housing. test different ways on the fuel gauge. you should find the 20 ohm gauge, a 50 ohm limiter and a combined 70 ohms.
i'm guessing your oil gauge is bad but... did you kill it. 12 volts will kill them. The 5 volts at zero resistance will too after a few minutes. Senders stop at 10 ohms. So when the wire would get knocked off the oil sender and short to zero resistance ground on the engine the gauge would peg, eventually overheat, and die. Good luck with it.