Join Date: Feb 2007
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As with many electronic thermometers the minus appears when the temperature is falling below zero - there just usn't a plus sign to show when it on the way up. Electronic temp systems can be notorously inaccurate because they rely on having a continous fixed voltage supply which is highly unlikely to happen in car electrics. You also have to consider the wind chill factor of a moving car. Even the height above ground can have serious affect. I have two outside thermometers - one mercury and one alcohol and both can vary as much as 5 degress and when I get into the car it is different again.
Thats the quirks of weather recording I'm afraid
Currently in madnoel10's garage:
Honda Civic 1.4l