Oil Pressure Sender electrics?

The Mopar sensors like this are designed to work off of lower voltage than the 12 system; it comes from a pulsed regulator in the dash, that passes through the gauge and the through the sensor in a series circuit to ground. That pulsed regulator gives an RMS DC voltage of around 5 volts to the gauge + sensor.

The sensor varies its resistance with pressure: low pressure is around 70-ish ohms and high pressure is around 10 ohms. So, if you use it with another gauge, you need to expect that resistance range. Other gauge systems use a much higher resistance range, with much lower sensor and gauge currents, so you need to do some serious adapting to make this work at all.