Block heater temperature mod?
 

My '07s factory block heater only works from -18°C(0°F) or colder, as is clearly marked on it.

I'd like to nix that "feature". Thanks GM, but at -17, the engine's a little stiff, still, and I'd like to do it a favor with a one hour warming before firing up...

Anywho, where's the sensor? I suspect it's right there at the "plug", but I thought I'd ask here before I take the cutters to it.