I have an old oil pressure gauge and sensor from a 1970 Land Rover. The gauge still works but the internal pressure plate in the sensor failed so I cut it open to see how it works. I've set it up on my bench with a power supply and it works with the gauge when I apply finger pressure to it. But I haven't been able to figure out how to measure the resistance and voltage drop as the pressure changes. The numbers on my DMM flash up and down as if I'm trying to measure a/c. Any suggestions on how to measure this?