Testing compressor

Well I found a compressor out of another wagon today. I can jump power to it with my battery pack and it runs so a good start. What wires do I need to jump to bench test the compressor? The solenoid only has two wires that I can see, and I tried jumping both but it never built air. I can feel some air coming from the crank vent but it doesn't appear to make any out of the tank. I'm guessing the solenoid is not letting the air through?

put a balloon over the outlet,. see what happens,.

I've got a pressure gauge I can use, but does the solenoid need power to let air out?