Anyone try using the thermo-control that's built into some electric fan shrouds?

Poked around online a bit and it seems that it is a resistor. So I'm thinking I tie this in series with the coil side of the relay so once it heats up enough (and I'm guessing the resistance drops), the relay will flip and turn the fan on. What do y'all think?

Also, this fan has two speeds but the car it came from only used one. I figure I'll just wire up "high" to a switch so I can flip it on if things get too toasty. Have any of you used 2-speed fans without AC?