But at that point would it really matter? I mean we're talking about avoiding ERDTT in cold climes. The added resistor in parallel would help offset the temp during the cold times so as to avoid the ERDTT, But once the temps move back up for summer we're no longer concerned about ERDTT so other than for the sake of having an easily calculated offset to an inaccurate temp display it'd work just fine. It's true, due to being a parallel resistor the change would not be linear (thanks Ohm's Law ha!), but if we're not concerned with the accuracy of the displayed temp we've solved the problem. Quite frankly if one is looking for a more permanent fix I like the idea of a simple switch which would add or remove the permanently installed resistor during the cold climes. We wouldn't need access to it often, so a simple switch rigged somewhere in the engine compartment that's easily accessible would be a simple, effective, and clean setup.