Testing an air compressor

[Calabrio]

I'll be damned if I can find the recent thread where this was discussed.
I have a couple of air ride compressors here and I'd like to test them outside of the car.

What was the proper way to power them directly from a car battery to test the motors?

 

[chicken]

red = power
black = ground
blue and white just open the vent so polarity dont matter