How do I test Blower Motor Resistor to veriy it is good? Visually it looks ok.

I installed a new Fan Motor,however when plugged in the motor runs continually on its own. The Fan switch has no control! Assume Resistor may now be the problem!The Resistor has components located in the middle of the assembly.I am familiar with electrical and electronic units, including Test Equipment.How do I know what ohm values I am looking for between the three (3) Pins on the assembly ??. Also,depending on what components are contained inside this Resistor,isn't it possible that an ohm meter may cause assembly component damage? Many thanks for any help you can provide.