It tells you how to test it. But Ill tell you too since I just tested one
You use a digital multimeter and ohm out the resistance between the black wire and the black/red wire. Resistance should be between 192 and 288 ohms
And then you ohm out resistance between the black wire and the white/red wire. Resistance should be between 16-24 ohms.
Note, temprature will affect the readings. The manual says its testing at 68 degrees farenheit.