I have a 2002 A6 and the temperature randomly switches between F* and C*. I know how to switch it, but when i start the car, it could be one or the other. Had the local dealer look at it when i had the timing service done, and they said " this is how you change it to either or". It functions properly with the exception of the temp. issue. Any ideas or input would be welcome.

 

Mine started doing the same thing about 30k miles ago (now at 184k). I would toggle it back to F and the next time I started it would come up as C. Lately, it will stay on F for multiple starts and then randomly change to C. I have used this opportunity to exercise my brain by manually converting F to C or vice versa. It works pretty good until the temperature goes under 32o F. No idea why it does it other than senility (the car, not mine) or the charm of the marque.