Kenworth Outside Air Temp Sensor

Bought a 2006 KW W900 with new style dash. Talked to Kenworth and asked about where the outside air temp sensor is. They said it was built into the factory mirror. The mirrors that are on here now are not factory. Was wondering what my options are to get it to read in the dash. They said that I would have to replace the entire mirror harness and the sensor is now built in the harness or something??? That was over $300 and I don't need to know the temp that bad. Just wondering if there was a cheaper option?

 

That's what I will end up doing if I cant figure it out. Would be nice if it would read out in the dash like its supposed to. Wasn't sure if I could somehow wire a sensor in to work with that.