Gentex Mirror says I’m a fozen popsicle!

I've read enough here to know all of you know your electrons better than I so...

I got a used Gentex 177 dual display 7 pin...(removed my basic Donelly auto dim mirror)...I probed which wires were +12, +12 reverse shutoff, and gnd.

I then hooked up a temp sensor & harness from another ebay auction...

I started the car and PRESTO!  everything was PERFECT! Compass read like a homeing pigeon, and the temp read 77 deg F.

After an hour test with the temp sensor sitting on passenger seat, I then un-hooked the Temp wires to begin the proper install through to the engine compartment, but from then on the reading is -39 deg F! After 2 minutes will raise to -37 deg F!

I may have attached/re-attached temp wires while car was running which normally is a bad idea for most electronics, but isnt this just a basic thermo-couple? Isn't the voltage only originating from the thermistor?

I tried re-attaching the wires every which way. It still recognizes when sensor is removed with "OC" displayed.

Could I have shorted/opened  something in my mirror?

I'm freezing here! HEEEEELP!!!!!

Problem thawed.

I can answer my own question. All the above is correct, but the interpolator part of the thermocouple (inside the mirror) goes out of scale if plugged in while vehicle is running. After a 30-45 minute adjustment period, the temp system will re-calibrate itself.

....now if all lifes problems were only so self-solving.