compass mirror question

[dazzasgotav8]

After finding one of these mirrors for sale i snapped it up and i got to say what an easy swap over unclip the covers twist the old one off unplug it plug new one in twist it on clip covers on hey presto done , then a reset and a spin in a few circles to calibrate all set.
My question is looking at the display before i fitted it i can see it has temperature letters in the display just wondering how i get it to read these temperatures and what they are , on a side not while i had the covers off i disconnected the rain sensor which fixed my intermittent wiper issues so that was another result.