Don't have the wiring diagram handy. One of the wires goes to the PBU. The other I think goes to ground. The PBU measures voltage, which varies with the resistance of the evap temp sensor, which varies with the temperature of the evap. Higher temp equals higher resistance. PBU decides whether to switch the compressor on & off based on this input.

Yours must be an open circuit - something isn't plugged in correctly, or the sensor was damaged. Infinite resistance corresponds with a very warm evap. You can test it by pulling the PBU using an inexpensive digital volt meter. Just have to know which pin on which of the two plugs it is. I don't know, and my shop manual isn't handy. Try searching the archives, maybe you'll find it.

- JimY