engine temperture sensor

I have a 89 cavalier wiht a 2.8 v 6. I located the coolant temperture sensor on the back of the engine...or atleast one of them. How do you test this? Everywhere I have looked says with a voltmeter one lead to the electrical lead on the sensor and the other on the sensor anywhere, for ground i suppose. I don't see how you test this. The main part is 6 sided bolted to the engine. On top is a wire. Does this wire just pull out? I don't want to rip it out if that isn't how it comes out. I know I'm looking for atleast a 200 ohm difference(i believe). This should tell me if the sensor is good or faulty.