Bad Oil Pressure Sensor - What's inside?

[mplafleur]

The oil pressure sensor on my SDL was bad. When you turned the key on, the gauge pegged full scale. I checked the sensor and it measure as an open circuit.

I'm going to put a mechanical gauge on and need an adapter for the 1/8"-27 threaded end on the lube. I've decide to make one from the old sensor. First I removed the housing. Here's what's inside.



It's a simple variable resistor. The wiper moves across the windings of the potentiometer. The wiper is connected to the case and one end of the winding is connected to a wire that goes to the single pin on the outside of the housing.
On this particular sensor, there is an open circuit between the wire and the first winding.



I've disconnected the spring here and rotated the plate to show how pressure will will push on the threaded set screw and cause the wiper to rotate across the windings.