AO Platinum Member
Join Date: Feb 2002
Location: The land that Time forgot
Cold water in the system makes the engine run rich (whatever the injector version of "choke" is) so you use more gas.
The switch is bolted half way up the radiator on the right hand side as you look at it (n/s or battery side of car) assuming you're peering over the front of the car.
You'll find it, as it has an electrical wire leading to it.
It's about £18.
The sensor for exterior temperature is in the driver's door mirror - it's that knobbly bit under the mirror body. -29 is the lowest temp it can display, I think. Might be worth cleaning all up the connections (particularly in the mirror end)... I think the display shows -29C if it has power but no reading.