To test the wiring I disconnected the sensor and hooked up the wiring to a new sensor and immersed that in boiling water.  Yes, I know this requires having or purchasing a new sensor, but if you don't get a reading you know it is in the wire or perhaps he voltage regulator behind the dash.

In my case I got a reading and knew I had to replace the sensor with the new one I had bought along with a bunch of other parts at the time.

First you may want to ensure that your connector is firmly in place.  If you can remove the sensor without pressing either or both detents on the sides, then it is not installed fully.  You may have to seat these detents with a small screw driver or fingernail.

John
LiMBO