'98 Mirror temp problem

[3-K]

I just bought an immaculate '98 Tahoe with one exception.
When I tap the Temp button on the rear view mirror it goes blank.
When I hold the Temp button for three seconds (according to the book it should give me the option between Celsius and Fahrenheit) all I get is OC on the display. Pushing Temp again does nothing, I have to wait until OC goes away.
Everything else on the mirror works just as it is supposed to, including the compass and auto dim features.
Before I replace the temp sensor (behind the grill I believe?) I was wondering if anyone else has encountered this 'code'?

This is my first 'Hoe' so be gentle.

Thank you for any help!

 

[SunlitComet]

it means open circuit. check the two wires leading out to sensor. Light green/black and brown for shorts or breaks if none then do the sensor. it is behind the grill.

 

[3-K]

Thank you very much!
All wires are good so it must be the sensor.