I know I'm getting power to the gauges for sure...when I hooked the battery up and keyed the power on, I saw the oil pressure gauge tick up slightly and stay there, and with the fuel tank and sender out the LED is still flashing away for low fuel.
Ya know, that's just plain wrong. Ignition on, motor off, oil gauge shouldn't move at all. Fuel sender unplugged, low fuel light should be constant on - I've never seen one that intentionally blinks. If's supposed to come on at 1/8 tank which is about 11 ohms at the sender. It will wink on and off when the fuel sloshes around but the gauge is dampened so it doesn't just bounce around constantly. I think I'd be close to yanking the cluster and putting the circuit board on the bench.
This is a pretty comprehensive gauge diag vid for 75-80 dodge trucks and mostly shouldn't be anything new. B body gauges work the same way, just different hardware. One thing I didn't pickup on when I stashed this away - he started with an oil sender for an idiot light then switched to an oil sender for a gauge.
https://www.youtube.com/watch?v=7X8Tiess12k
