I've measured the wires, both the yellow and white appear to have the same output, but don't show continuity so are not connected together.
WHAT IS THE OUTPUT ?
no voltage ?Put it in the fridge for 15 minutes and measure the resistance again.
It's probably a thermociouple.. Thermisters don',t generate voltage.
20mV from a thermocouple at room temperature? Are you kidding? That's usually 100's or 1000's of degrees.