It's an 89 Civic SI. When you turn the AC on you hear the compressor spinning and you hear it click on. Nothing at all comes out of the vents however, not even warm air. I'm pretty sure it's something to do with the blower motor so my question is, is there any way to test out the blower motor control module/ resistor? I want to know if it's either the resistor or the module before I start buying parts.

 

Take the resistor assembly out and test it with a ohm meter. Usually at least one of the fan speeds work, so if none are working it may be something else. I would then unplug the blower motor and test for continuity across the motor.