IVR/Instrument Cluster Voltage Limiter on a 65 Dart

Dana67Dart said

There was a recent post about IVR and someone posted a photo of the in fuel gauge IVR. your IVR could be stuck in the closed position supplying 12V to the gauges. do as Redfish said, with the fuel gauge sender (at the tank) disconnected turn key on for a short period of time and see what the fuel gauge does. if it stays at empty I would be looking into the internal IVR in your fuel gauge / resistance in the fuel gauge wiring / sender. the other gauges work the same high numerical resistance ~70-80 ohms or higher = empty, low temp and low oil pressure too. low resistance ~10 ohms should read full, hot and high oil pressure.

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The mechanical limiter will send higher output during warm up, makes needles move faster to where they are going. Switch on with cold stopped engine, fuel gauge responds, oil and temp don't move. If there is short in temp gauge circuit, limiter senses that and sends all it can. Current takes that path of least resistance. With the minimum of 80 ohms resistance at the fuel sender, and too much current, How would the fuel gauge respond? I don't know that it would go to 3/4 of range but I'll bet my quarter needle would leave home.
What I do know... if the temp sender path is shorted to ground, the temp gauge will die eventually.
If the limiter sticks closed the gauge with least resistance ( typically the fuel gauge ) will get lions share of the voltage, read way high. The limiter should fail internally but that doesn't always happen. Instead, the copper trace on the circuit board that carries 12 volts to the limiter will burn open as if it were a fusible link.