The ambient temp reading inaccurate.
The ambient temp reading in Subaru outback stays the same. (starts at 77 when back out of garage and stays at 77 for the whole drive. I replaced the sensor and when I tried it, still read 77 for a drive of 3 miles around neighborhood. It seemed to have 'gone bad' after i had work done on roof where they blew a fuse for interior lights. Don't know if related.