My wife's 2003 Seville has read 50°F for about a year now but we never really saw a need to fix it. However, as we were driving last night the temperature display jumped from 50 down to -39°F and began fogging up the windshield as it automatically turned up the heat inside the car. The temp continued to jump randomly from -39°F up to 50°F and back down again for the remainder of the drive. I am assuming that this is only a bad external temperature sensor but wanted to see if anyone else has experienced this before? I thought that it was very odd for it to stay at 50°F consistently for a year and then begin jumping around randomly.